in summary , our cpc revenue depends on the number of hotel shoppers that are interested in a property , whether there is a commerce link available for that hotel shopper to click on for that property , whether there are several commerce choices available for that property so the hotel shopper has the benefit of pricing and availability from multiple sources and what our customers are willing to pay us for the lead . key drivers of display-based advertising revenue for the years ended december 31 , 2013 , 2012 and 2011 , 13 % , 12 % and 13 % , respectively , of our total revenue came from our display-based advertising product . the key drivers of our display-based advertising revenue include the growth in number of impressions , or the number of times an ad is displayed on our site , and the cost per thousand impressions , or cpm . our number of impressions sold increased 34 % for the year ended december 31 , 2013 over 2012 and increased 6 % for the year ended december 31 , 2012 over 2011 , while pricing decreased 5 % for the year ended december 31 , 2013 over 2012 and increased 1 % for the years ended december 31 , 2012 over 2011 , according to our customer logs . key growth areas we continue to invest in areas of potential growth , including our social , mobile and global initiatives as well as our business listings and vacation rentals products . mobile . mobile is an investment area that is geared towards creating a more complete user experience by reinforcing the tripadvisor brand when users are in-market . in the year ended december 31 , 2013 , we saw strong mobile user uptake , as aggregate downloads of our tripadvisor , city guides , seatguru , jetsetter and gateguru mobile apps reached 82 million downloads and average monthly unique visitors via smartphone and tablet devices grew over 170 % year-over-year from 32 million to 87 million , according to company logs . we believe that travelers will increasingly use mobile devices , including smartphones and tablets , to conduct travel research and planning . social . our wisdom of friends initiative is a core component of our strategic growth plan . we believe that having a strong social presence improves engagement on our sites and improves the sites ' stickiness amongst the users . as a result , we continue to deepen our integration with facebook . as of december 31 , 2013 , and according to appdata , an independent application tracking traffic service , tripadvisor has averaged over 36 million monthly facebook users via its tripadvisor facebook application . we offer these facebook users a more personalized and social travel planning experience that enables travelers to engage with their own facebook friends ' reviews and opinions when planning their perfect trip on tripadvisor . business listings . created in early 2010 , our business listings product enables hotel and accommodation owners to list pertinent property information on tripadvisor , bringing them closer to potential customers and thereby increasing direct bookings . in the year ended december 31 , 2013 , we grew our business listings customer base over 38 % to 69,000 subscribers , representing approximately 9 % of our current hotel and accommodation listings on tripadvisor branded sites . we continue to expand our sales force and improve features to grow our subscriber base . vacation rentals . as of december 31 , 2013 , we had amassed an inventory of approximately 550,000 properties , up more than 80 % during the year , across our tripadvisor vacation rentals , u.s.-based flipkey , and european-based holiday lettings and niumba . we offer individual property owners and property managers the ability to list using a subscription-based fee structure or a free-to-list , commission-based option and we believe our highly-engaged and motivated user community creates a competitive advantage for us in this market . 40 current trends affecting our business increasing competition . the travel review industry and , more generally , the business of collecting and aggregating travel-related resources and information , continue to be increasingly competitive . in recent years , an increasing number of companies , such as search companies google , inc. and baidu.com , inc. and several large online travel agencies , have begun to collect and aggregate travel information and resources . we plan to continue to invest in order to remain the leading source of travel reviews as well as continuing to enhance our content and user experience . refer to our discussion above in competition in item 1 business section for additional information on our competition . increasing use of internet and social media to access travel information . commerce , information and advertising continue to migrate to the internet and away from traditional media outlets . we believe that this trend will continue to create strategic growth opportunities , allowing us to attract new consumers and develop unique and effective advertising solutions . consumers are increasingly using online social media channels , such as facebook and twitter , as a means to communicate and exchange information , including travel information and opinions . we have made significant efforts related to social networking in order to leverage the expanding use of this channel and enhance traffic diversification and user engagement . we are also continually adapting our user experience in response to a changing internet environment and usage trends . for example , in 2012 , we invested in building and introducing to users hotel metasearch functionality for our smartphone platforms and in 2013 , we completed the process of implementing hotel metasearch functionality on our desktop and tablet platforms . refer to our metasearch discussion above under improving the hotel shopper experience in the our strategy section in item 1 business for additional information on our hotel metasearch transition . increasing mobile usage . story_separator_special_tag 48 general and administrative general and administrative expense consists primarily of personnel and related overhead costs , including executive leadership , finance , legal and human resource functions and stock-based compensation as well as professional service fees and other fees including audit , legal , tax and accounting , and other costs including bad debt expense and our charitable foundation costs . replace_table_token_17_th 2013 vs. 2012 general and administrative costs increased $ 22 million during the year ended december 31 , 2013 , when compared to the same period in 2012 , primarily due to increased personnel costs related to an increase in stock-based compensation , as well as increased headcount to support business growth and additional professional service fees in order to support our operations and an increase in our bad debt provision . 2012 vs. 2011 general and administrative costs increased $ 31 million during the year ended december 31 , 2012 , when compared to the same period in 2011 , due to increased personnel and overhead costs related to an increase in stock based compensation , as well as increased headcount to support business growth , and a full year of costs related to additional headcount and professional service fees to support our operations as a standalone public company in 2012. we also incurred increased professional service fees primarily related to legal and tax initiatives . in addition , in connection with the spin-off , we assumed expedia 's obligation to fund a charitable foundation ( see note 12 commitments and contingencies in the notes to the consolidated and combined financial statements ) . our expense related to the funding of this charitable foundation was $ 7 million for the year ended december 31 , 2012. shared services fee with expedia prior to the spin-off , our shared services fee was comprised of allocations from expedia for accounting , legal , tax , corporate development , treasury , financial reporting , real estate management and included an allocation of employee compensation within these functions . these allocations were determined based on what we and expedia considered to be reasonable reflections of the utilization of services provided or the benefit received by us . replace_table_token_18_th shared services fee costs incurred for the use of expedia shared services ceased in connection with the spin-off . refer to note 15 related party transactions  in the notes to our consolidated and combined financial statements for further information on our relationship with expedia . 49 depreciation replace_table_token_19_th 2013 vs. 2012 depreciation expense increased $ 9 million during the year ended december 31 , 2013 when compared to the same period in 2012 primarily due to increased amortization related to capitalized software and website development costs . 2012 vs. 2011 depreciation expense increased $ 2 million during the year ended december 31 , 2012 when compared to the same period in 2011 primarily due to increased amortization related to capitalized software and website development costs and additional depreciation of $ 1 million related to purchased software licenses and leasehold improvements . amortization of intangible assets replace_table_token_20_th 2013 vs. 2012 amortization of intangible assets did not materially change during the year ended december 31 , 2013 when compared to the same period in 2012. amortization related to acquired definite lived intangibles from business acquisitions during 2013 was more than offset by the completion of amortization related to certain technology intangible assets from prior years . 2012 vs. 2011 amortization of intangible assets decreased $ 2 million during the year ended december 31 , 2012 when compared to the same period in 2011 , primarily due to the completion of amortization related to certain technology intangible assets . interest income interest income primarily consists of interest earned and amortization of discounts and premiums on our marketable securities . replace_table_token_21_th 50 2013 vs. 2012 interest income increased $ 1 million during the year ended december 31 , 2013 when compared to the same period in 2012. the increase in interest income is primarily due to the fact that we began investing in marketable securities during the fourth quarter of 2012. refer to note 4 financial instruments  for additional information on our current portfolio as of december 31 , 2013 . 2012 vs. 2011 interest income did not materially change during the year ended december 31 , 2012 when compared to the same period in 2011. interest expense interest expense primarily consists of interest incurred , commitment fees and debt issuance cost amortization related to our credit agreement and chinese credit facilities . replace_table_token_22_th 2013 vs. 2012 the decrease in interest expense is primarily due to the lower outstanding borrowings and effective interest rates during the year ended december 31 , 2013 over the same period during 2012 related to our term loan . refer to note 8 debt  for additional information on our outstanding borrowing facilities . 2012 vs. 2011 the increase in interest expense is related to interest incurred as a result of us entering into our credit agreement for the year ending december 31 , 2012 over the same period during 2011. other expense , net replace_table_token_23_th other , net is primarily comprised of net foreign exchange losses and disposal of fixed assets for the periods presented . provision for income taxes replace_table_token_24_th 51 2013 vs. 2012 our effective tax rates for the years ended december 31 , 2013 and 2012 were 27.8 % and 31.0 % , respectively . our effective tax rate is less than the federal statutory rate primarily due to earnings in jurisdictions outside the united states , where our effective tax rate is lower . this is partly driven by the current statutory tax rate of 23 % in the united kingdom and our tax incentive on qualifying income in singapore granted by the singapore economic development board in 2011. our effective tax rate is partially offset by state income taxes , non-deductible stock compensation and accruals on uncertain tax positions . the decrease in

sources and uses of cash our cash flows from operating , investing and financing activities , as reflected in the consolidated and combined statements of cash flows , are summarized in the following table : replace_table_token_26_th our principal source of liquidity is cash flows generated from operations , although liquidity needs can also be met through drawdowns under our credit facilities discussed above . as of december 31 , 2013 and 2012 , we had $ 671 million and $ 586 million of cash , cash equivalents and short and long-term available-for-sale marketable securities . as of december 31 , 2013 approximately $ 442 million of our cash , cash equivalents and short and long-term marketable securities are held by our international subsidiaries , primarily in the united kingdom , and are related to earnings we intend to reinvest permanently outside the united states . cumulative undistributed earnings of foreign subsidiaries that we intend to indefinitely reinvest outside of the united states totaled approximately $ 481 million as of december 31 , 2013. should we distribute , or be treated under certain u.s. tax rules as having distributed , the earnings of foreign subsidiaries in the form of dividends or otherwise , we may be subject to u.s. income taxes . determination of the amount of any unrecognized deferred income tax liability on this temporary difference is not practicable because of the complexities of the hypothetical calculation . cash held is primarily denominated in u.s. dollars . historically , the cash we generate has been sufficient to fund our working capital requirements , capital expenditures and to meet our long term debt obligations and other financial commitments .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```sources and uses of cash our cash flows from operating , investing and financing activities , as reflected in the consolidated and combined statements of cash flows , are summarized in the following table : replace_table_token_26_th our principal source of liquidity is cash flows generated from operations , although liquidity needs can also be met through drawdowns under our credit facilities discussed above . as of december 31 , 2013 and 2012 , we had $ 671 million and $ 586 million of cash , cash equivalents and short and long-term available-for-sale marketable securities . as of december 31 , 2013 approximately $ 442 million of our cash , cash equivalents and short and long-term marketable securities are held by our international subsidiaries , primarily in the united kingdom , and are related to earnings we intend to reinvest permanently outside the united states . cumulative undistributed earnings of foreign subsidiaries that we intend to indefinitely reinvest outside of the united states totaled approximately $ 481 million as of december 31 , 2013. should we distribute , or be treated under certain u.s. tax rules as having distributed , the earnings of foreign subsidiaries in the form of dividends or otherwise , we may be subject to u.s. income taxes . determination of the amount of any unrecognized deferred income tax liability on this temporary difference is not practicable because of the complexities of the hypothetical calculation . cash held is primarily denominated in u.s. dollars . historically , the cash we generate has been sufficient to fund our working capital requirements , capital expenditures and to meet our long term debt obligations and other financial commitments .
```    
 Suspicious Activity Report : in summary , our cpc revenue depends on the number of hotel shoppers that are interested in a property , whether there is a commerce link available for that hotel shopper to click on for that property , whether there are several commerce choices available for that property so the hotel shopper has the benefit of pricing and availability from multiple sources and what our customers are willing to pay us for the lead . key drivers of display-based advertising revenue for the years ended december 31 , 2013 , 2012 and 2011 , 13 % , 12 % and 13 % , respectively , of our total revenue came from our display-based advertising product . the key drivers of our display-based advertising revenue include the growth in number of impressions , or the number of times an ad is displayed on our site , and the cost per thousand impressions , or cpm . our number of impressions sold increased 34 % for the year ended december 31 , 2013 over 2012 and increased 6 % for the year ended december 31 , 2012 over 2011 , while pricing decreased 5 % for the year ended december 31 , 2013 over 2012 and increased 1 % for the years ended december 31 , 2012 over 2011 , according to our customer logs . key growth areas we continue to invest in areas of potential growth , including our social , mobile and global initiatives as well as our business listings and vacation rentals products . mobile . mobile is an investment area that is geared towards creating a more complete user experience by reinforcing the tripadvisor brand when users are in-market . in the year ended december 31 , 2013 , we saw strong mobile user uptake , as aggregate downloads of our tripadvisor , city guides , seatguru , jetsetter and gateguru mobile apps reached 82 million downloads and average monthly unique visitors via smartphone and tablet devices grew over 170 % year-over-year from 32 million to 87 million , according to company logs . we believe that travelers will increasingly use mobile devices , including smartphones and tablets , to conduct travel research and planning . social . our wisdom of friends initiative is a core component of our strategic growth plan . we believe that having a strong social presence improves engagement on our sites and improves the sites ' stickiness amongst the users . as a result , we continue to deepen our integration with facebook . as of december 31 , 2013 , and according to appdata , an independent application tracking traffic service , tripadvisor has averaged over 36 million monthly facebook users via its tripadvisor facebook application . we offer these facebook users a more personalized and social travel planning experience that enables travelers to engage with their own facebook friends ' reviews and opinions when planning their perfect trip on tripadvisor . business listings . created in early 2010 , our business listings product enables hotel and accommodation owners to list pertinent property information on tripadvisor , bringing them closer to potential customers and thereby increasing direct bookings . in the year ended december 31 , 2013 , we grew our business listings customer base over 38 % to 69,000 subscribers , representing approximately 9 % of our current hotel and accommodation listings on tripadvisor branded sites . we continue to expand our sales force and improve features to grow our subscriber base . vacation rentals . as of december 31 , 2013 , we had amassed an inventory of approximately 550,000 properties , up more than 80 % during the year , across our tripadvisor vacation rentals , u.s.-based flipkey , and european-based holiday lettings and niumba . we offer individual property owners and property managers the ability to list using a subscription-based fee structure or a free-to-list , commission-based option and we believe our highly-engaged and motivated user community creates a competitive advantage for us in this market . 40 current trends affecting our business increasing competition . the travel review industry and , more generally , the business of collecting and aggregating travel-related resources and information , continue to be increasingly competitive . in recent years , an increasing number of companies , such as search companies google , inc. and baidu.com , inc. and several large online travel agencies , have begun to collect and aggregate travel information and resources . we plan to continue to invest in order to remain the leading source of travel reviews as well as continuing to enhance our content and user experience . refer to our discussion above in competition in item 1 business section for additional information on our competition . increasing use of internet and social media to access travel information . commerce , information and advertising continue to migrate to the internet and away from traditional media outlets . we believe that this trend will continue to create strategic growth opportunities , allowing us to attract new consumers and develop unique and effective advertising solutions . consumers are increasingly using online social media channels , such as facebook and twitter , as a means to communicate and exchange information , including travel information and opinions . we have made significant efforts related to social networking in order to leverage the expanding use of this channel and enhance traffic diversification and user engagement . we are also continually adapting our user experience in response to a changing internet environment and usage trends . for example , in 2012 , we invested in building and introducing to users hotel metasearch functionality for our smartphone platforms and in 2013 , we completed the process of implementing hotel metasearch functionality on our desktop and tablet platforms . refer to our metasearch discussion above under improving the hotel shopper experience in the our strategy section in item 1 business for additional information on our hotel metasearch transition . increasing mobile usage . story_separator_special_tag 48 general and administrative general and administrative expense consists primarily of personnel and related overhead costs , including executive leadership , finance , legal and human resource functions and stock-based compensation as well as professional service fees and other fees including audit , legal , tax and accounting , and other costs including bad debt expense and our charitable foundation costs . replace_table_token_17_th 2013 vs. 2012 general and administrative costs increased $ 22 million during the year ended december 31 , 2013 , when compared to the same period in 2012 , primarily due to increased personnel costs related to an increase in stock-based compensation , as well as increased headcount to support business growth and additional professional service fees in order to support our operations and an increase in our bad debt provision . 2012 vs. 2011 general and administrative costs increased $ 31 million during the year ended december 31 , 2012 , when compared to the same period in 2011 , due to increased personnel and overhead costs related to an increase in stock based compensation , as well as increased headcount to support business growth , and a full year of costs related to additional headcount and professional service fees to support our operations as a standalone public company in 2012. we also incurred increased professional service fees primarily related to legal and tax initiatives . in addition , in connection with the spin-off , we assumed expedia 's obligation to fund a charitable foundation ( see note 12 commitments and contingencies in the notes to the consolidated and combined financial statements ) . our expense related to the funding of this charitable foundation was $ 7 million for the year ended december 31 , 2012. shared services fee with expedia prior to the spin-off , our shared services fee was comprised of allocations from expedia for accounting , legal , tax , corporate development , treasury , financial reporting , real estate management and included an allocation of employee compensation within these functions . these allocations were determined based on what we and expedia considered to be reasonable reflections of the utilization of services provided or the benefit received by us . replace_table_token_18_th shared services fee costs incurred for the use of expedia shared services ceased in connection with the spin-off . refer to note 15 related party transactions  in the notes to our consolidated and combined financial statements for further information on our relationship with expedia . 49 depreciation replace_table_token_19_th 2013 vs. 2012 depreciation expense increased $ 9 million during the year ended december 31 , 2013 when compared to the same period in 2012 primarily due to increased amortization related to capitalized software and website development costs . 2012 vs. 2011 depreciation expense increased $ 2 million during the year ended december 31 , 2012 when compared to the same period in 2011 primarily due to increased amortization related to capitalized software and website development costs and additional depreciation of $ 1 million related to purchased software licenses and leasehold improvements . amortization of intangible assets replace_table_token_20_th 2013 vs. 2012 amortization of intangible assets did not materially change during the year ended december 31 , 2013 when compared to the same period in 2012. amortization related to acquired definite lived intangibles from business acquisitions during 2013 was more than offset by the completion of amortization related to certain technology intangible assets from prior years . 2012 vs. 2011 amortization of intangible assets decreased $ 2 million during the year ended december 31 , 2012 when compared to the same period in 2011 , primarily due to the completion of amortization related to certain technology intangible assets . interest income interest income primarily consists of interest earned and amortization of discounts and premiums on our marketable securities . replace_table_token_21_th 50 2013 vs. 2012 interest income increased $ 1 million during the year ended december 31 , 2013 when compared to the same period in 2012. the increase in interest income is primarily due to the fact that we began investing in marketable securities during the fourth quarter of 2012. refer to note 4 financial instruments  for additional information on our current portfolio as of december 31 , 2013 . 2012 vs. 2011 interest income did not materially change during the year ended december 31 , 2012 when compared to the same period in 2011. interest expense interest expense primarily consists of interest incurred , commitment fees and debt issuance cost amortization related to our credit agreement and chinese credit facilities . replace_table_token_22_th 2013 vs. 2012 the decrease in interest expense is primarily due to the lower outstanding borrowings and effective interest rates during the year ended december 31 , 2013 over the same period during 2012 related to our term loan . refer to note 8 debt  for additional information on our outstanding borrowing facilities . 2012 vs. 2011 the increase in interest expense is related to interest incurred as a result of us entering into our credit agreement for the year ending december 31 , 2012 over the same period during 2011. other expense , net replace_table_token_23_th other , net is primarily comprised of net foreign exchange losses and disposal of fixed assets for the periods presented . provision for income taxes replace_table_token_24_th 51 2013 vs. 2012 our effective tax rates for the years ended december 31 , 2013 and 2012 were 27.8 % and 31.0 % , respectively . our effective tax rate is less than the federal statutory rate primarily due to earnings in jurisdictions outside the united states , where our effective tax rate is lower . this is partly driven by the current statutory tax rate of 23 % in the united kingdom and our tax incentive on qualifying income in singapore granted by the singapore economic development board in 2011. our effective tax rate is partially offset by state income taxes , non-deductible stock compensation and accruals on uncertain tax positions . the decrease in

