22 results of operati ons set forth below are our results of operations for the year ended december 31 , 2015 compared with the year ended december 31 , 2014 and the year ended december 31 , 2014 compared with the year ended december 31 , 2013. replace_table_token_4_th our results of operations discussed below include the impact of purchase price accounting adjustments associated with the july 2008 merger between our wholly owned subsidiary , vernon merger corporation , and xm satellite radio holdings inc. ( the “ merger ” ) . the purchase price accounting adjustments related to the merger , include the : ( i ) elimination of deferred revenue associated with the investment in xm canada , ( ii ) recognition of deferred subscriber revenues not recognized in purchase price accounting , and ( iii ) elimination of the benefit of deferred credits on executory contracts , which are primarily attributable to third party arrangements with an oem and programming providers . the deferred credits on executory contracts attributable to third party arrangements with an oem included in revenue share and royalties , subscriber acquisition costs , and sales and marketing concluded with the expiration of the acquired contract during 2013. the purchase price accounting adjustments related to programming providers concluded with the expiration of the acquired contract in june 2015. the impact of these purchase price accounting adjustments is detailed in our adjusted revenues and operating expenses tables on pages 37 through 38 of our glossary . total revenue subscriber revenue includes subscription , activation and other fees . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , subscriber revenue was $ 3,824,793 and $ 3,554,302 , respectively , an increase of 8 % , or $ 270,491. the increase was primarily attributable to an 8 % increase in the daily weighted average number of subscribers and increases in certain of our self-pay subscription rates , partially offset by subscription discounts and limited channel plans offered in customer acquisition and retention programs . 23 · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , subscriber revenue was $ 3,554,302 and $ 3,284,660 , respectively , an increase of 8 % , or $ 269,642 . the increase was primarily attributable to a 6 % increase in the daily weighted average number of su bscribers , the inclusion of a full year of subscription revenue generated by our connected vehicle business and the increase in certain of our subscription rates beginning in january 2014. these increases were partially offset by subscription discounts and limited channel plans offered in customer acquisition and retention programs , a change in an agreement with an automaker and a rental car company , and an increasing number of lifetime subscription plans that ha d reached full revenue recognition . we expect subscriber revenues to increase based on the growth of our subscriber base , including the increases in certain of our subscription rates and the sale of additional services to subscribers . advertising revenue includes the sale of advertising on certain non-music channels . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , advertising revenue was $ 122,292 and $ 100,982 , respectively , an increase of 21 % , or $ 21,310. the increase was primarily due to a greater number of advertising spots sold and transmitted as well as increases in rates charged per spot . · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , advertising revenue was $ 100,982 and $ 89,288 , respectively , an increase of 13 % , or $ 11,694. the increase was primarily due to a greater number of advertising spots sold and transmitted , as well as increases in rates charged per spot . we expect our advertising revenue to continue to grow as more advertisers are attracted to our national platform and growing subscriber base and as we launch additional non-music channels . equipment revenue includes revenue and royalties from the sale of satellite radios , components and accessories . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , equipment revenue was $ 110,923 and $ 104,661 , respectively , an increase of 6 % , or $ 6,262. the increase was driven by royalties from higher oem production and sales to distributors , partially offset by lower direct to consumer sales . · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , equipment revenue was $ 104,661 and $ 80,573 , respectively , an increase of 30 % , or $ 24,088. the increase was driven by higher sales to distributors and royalties from oem production , partially offset by lower per unit revenue on direct to consumer sales . we expect equipment revenue to fluctuate based on oem production for which we receive royalty payments for our technology and , to a lesser extent , on the volume of equipment sales in our aftermarket and direct to consumer business . other revenue includes amounts earned from subscribers for the u.s. music royalty fee , revenue from our connected vehicle business and our canadian affiliate and ancillary revenues . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , other revenue was $ 512,050 and $ 421,150 , respectively , an increase of 22 % , or $ 90,900. the increase was driven by revenues from the u.s. music royalty fee as the number of subscribers subject to the 13.9 % rate increased along with an overall increase in subscribers , higher revenue generated from our connected vehicle business , and increased revenue from our canadian affiliate . story_separator_special_tag our annual effective tax rate for the year ended december 31 , 2013 was 40.8 % , primarily as a result of non-deductible expenses related to the loss on change in value of derivatives . key operating metrics in this section , we present certain financial and operating performance measures that are not calculated and presented in accordance with generally accepted accounting principles in the united states ( “ non-gaap ” ) . these metrics include : average monthly revenue per subscriber , or arpu ; customer service and billing expenses , per average subscriber ; subscriber acquisition cost , or sac , per installation ; free cash flow ; and adjusted ebitda . these measures exclude the impact of share-based payment expense and certain purchase price accounting adjustments related to the merger , which include the : ( i ) elimination of deferred revenue associated with the investment in xm canada , ( ii ) recognition of deferred subscriber revenues not recognized in purchase price accounting , and ( iii ) elimination of the benefit of deferred credits on executory contracts , which are primarily attributable to third party arrangements with an oem and programming providers . additionally , when applicable , our adjusted ebitda and free cash flow metrics exclude the effect of any significant items that do not relate to the on-going performance of our business , such as settlements related to our historical use of pre-1972 sound recordings . we use these non-gaap financial measures to manage our business , to set operational goals and as a basis for determining performance-based compensation for our employees . free cash flow is a metric that our management and board of directors use to evaluate the cash generated by our operations , net of capital expenditures and other investment activity and significant items that do not relate to the on-going performance of our business . in a capital intensive business , with significant investments in satellites , we look at our operating cash flow , net of these investing cash outflows , to determine cash available for future subscriber acquisition and capital expenditures , to repurchase or retire debt , to acquire other companies and to evaluate our ability to return capital to stockholders . we believe free cash flow is an indicator of the long-term financial stability of our business . free cash flow , which is reconciled to “ net cash provided by operating activities , ” is a non-gaap financial measure . this measure can be calculated by deducting amounts under the captions “ additions to property and equipment ” , deducting or adding restricted and other investment activity and the return of capital from investment in unconsolidated entity from “ net cash provided by operating activities ” from the consolidated statements of cash flows , adjusted for any significant legal settlements . free cash flow should be used in conjunction with other gaap financial performance measures and may not be comparable to free cash flow measures presented by other companies . free cash flow should be viewed as a supplemental measure rather than an alternative measure of cash flows from operating activities , as determined in accordance with gaap . free cash flow is limited and does not represent remaining cash flows available for discretionary expenditures due to the fact that the measure does not deduct the payments required for debt maturities . we believe free cash flow provides useful supplemental information to investors regarding our current and projected cash flow , along with other gaap measures ( such as cash flows from operating and investing activities ) , to determine our financial condition , and to compare our operating performance to other communications , entertainment and media companies . we have excluded the $ 210,000 payment related to the pre-1972 sound recordings legal settlement from our free cash flow calculation in the year ended december 31 , 2015. we believe these non-gaap financial measures provide useful information to investors regarding our financial condition and results of operations . we believe investors find these non-gaap financial performance measures useful in evaluating our core trends because it provides a direct view of our underlying contractual costs . we believe investors use our current and projected adjusted ebitda to estimate our current or prospective enterprise value and to make investment decisions . by providing these non-gaap financial measures , together with the reconciliations to the most directly comparable gaap measure , we believe we are enhancing investors ' understanding of our business and our results of operations . 29 these non-gaap financial measures should be viewed in addition to , and not as an alternative for or superior to , our reported results prepared in accordance with gaap . in addition , these non-gaap financial measures may not be comparable to sim ilarly-titled measures by other companies . please refer to the glossary ( pages 36 through 40 ) for a further discussion of such non-gaap financial measures and reconciliations to the most directly comparable gaap measure . the following table contains our key operating metrics based on our adjusted results of operations for the years ended december 31 , 2015 , 2014 and 2013 . subscribers and subscription related revenues and expenses associated with our connected vehicle services are not included in our subscr iber count or subscriber-based operating metrics : replace_table_token_5_th ( a ) note : amounts may not sum as a result of rounding . subscribers . at december 31 , 2015 , we had approximately 29.6 million subscribers , an increase of approximately 2.3 million subscribers , or 8 % , from the approximate 27.3 million subscribers as of december 31 , 2014 . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , net additions were 2,283 thousand and 1,752 thousand , respectively , an increase of 30 % , or 531 thousand . the increase in subscribers was primarily due to increases in original and

includes interest on outstanding debt . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , interest expense was $ 299,103 and $ 269,010 , respectively , an increase of 11 % , or $ 30,093 . the increase was primarily due to higher average debt during the year ended december 31 , 2015 compared to the year ended december 31 , 2014. the increase was partially offset by lower average interest rates resulting from the redemption and conversion of higher interest rate debt during 2014 . · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , interest expense was $ 269,010 and $ 204,671 , respectively , an increase of 31 % , or $ 64,339. the increase was primarily due to higher average debt and a 27 reduction in interest capitalized following the launch of our fm -6 satellite . the increase was partially offset by lower average interest rates resulting from the redemption or repayment of higher interest rate debt throughout 2013. we expect interest expense to increase in future periods to the extent the amount of our total debt outstanding increases . loss on extinguishment of debt and credit facilities , net , includes losses incurred as a result of the conversion and retirement of certain debt . · 2015 vs. 2014 : there was no loss on extinguishment of debt and credit facilities for the years ended december 31 , 2015 and 2014 . · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , loss on extinguishment of debt and credit facilities , net , was $ 0 and $ 190,577 , respectively .


 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.
     ```includes interest on outstanding debt . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , interest expense was $ 299,103 and $ 269,010 , respectively , an increase of 11 % , or $ 30,093 . the increase was primarily due to higher average debt during the year ended december 31 , 2015 compared to the year ended december 31 , 2014. the increase was partially offset by lower average interest rates resulting from the redemption and conversion of higher interest rate debt during 2014 . · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , interest expense was $ 269,010 and $ 204,671 , respectively , an increase of 31 % , or $ 64,339. the increase was primarily due to higher average debt and a 27 reduction in interest capitalized following the launch of our fm -6 satellite . the increase was partially offset by lower average interest rates resulting from the redemption or repayment of higher interest rate debt throughout 2013. we expect interest expense to increase in future periods to the extent the amount of our total debt outstanding increases . loss on extinguishment of debt and credit facilities , net , includes losses incurred as a result of the conversion and retirement of certain debt . · 2015 vs. 2014 : there was no loss on extinguishment of debt and credit facilities for the years ended december 31 , 2015 and 2014 . · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , loss on extinguishment of debt and credit facilities , net , was $ 0 and $ 190,577 , respectively .
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 Suspicious Activity Report : 22 results of operati ons set forth below are our results of operations for the year ended december 31 , 2015 compared with the year ended december 31 , 2014 and the year ended december 31 , 2014 compared with the year ended december 31 , 2013. replace_table_token_4_th our results of operations discussed below include the impact of purchase price accounting adjustments associated with the july 2008 merger between our wholly owned subsidiary , vernon merger corporation , and xm satellite radio holdings inc. ( the “ merger ” ) . the purchase price accounting adjustments related to the merger , include the : ( i ) elimination of deferred revenue associated with the investment in xm canada , ( ii ) recognition of deferred subscriber revenues not recognized in purchase price accounting , and ( iii ) elimination of the benefit of deferred credits on executory contracts , which are primarily attributable to third party arrangements with an oem and programming providers . the deferred credits on executory contracts attributable to third party arrangements with an oem included in revenue share and royalties , subscriber acquisition costs , and sales and marketing concluded with the expiration of the acquired contract during 2013. the purchase price accounting adjustments related to programming providers concluded with the expiration of the acquired contract in june 2015. the impact of these purchase price accounting adjustments is detailed in our adjusted revenues and operating expenses tables on pages 37 through 38 of our glossary . total revenue subscriber revenue includes subscription , activation and other fees . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , subscriber revenue was $ 3,824,793 and $ 3,554,302 , respectively , an increase of 8 % , or $ 270,491. the increase was primarily attributable to an 8 % increase in the daily weighted average number of subscribers and increases in certain of our self-pay subscription rates , partially offset by subscription discounts and limited channel plans offered in customer acquisition and retention programs . 23 · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , subscriber revenue was $ 3,554,302 and $ 3,284,660 , respectively , an increase of 8 % , or $ 269,642 . the increase was primarily attributable to a 6 % increase in the daily weighted average number of su bscribers , the inclusion of a full year of subscription revenue generated by our connected vehicle business and the increase in certain of our subscription rates beginning in january 2014. these increases were partially offset by subscription discounts and limited channel plans offered in customer acquisition and retention programs , a change in an agreement with an automaker and a rental car company , and an increasing number of lifetime subscription plans that ha d reached full revenue recognition . we expect subscriber revenues to increase based on the growth of our subscriber base , including the increases in certain of our subscription rates and the sale of additional services to subscribers . advertising revenue includes the sale of advertising on certain non-music channels . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , advertising revenue was $ 122,292 and $ 100,982 , respectively , an increase of 21 % , or $ 21,310. the increase was primarily due to a greater number of advertising spots sold and transmitted as well as increases in rates charged per spot . · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , advertising revenue was $ 100,982 and $ 89,288 , respectively , an increase of 13 % , or $ 11,694. the increase was primarily due to a greater number of advertising spots sold and transmitted , as well as increases in rates charged per spot . we expect our advertising revenue to continue to grow as more advertisers are attracted to our national platform and growing subscriber base and as we launch additional non-music channels . equipment revenue includes revenue and royalties from the sale of satellite radios , components and accessories . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , equipment revenue was $ 110,923 and $ 104,661 , respectively , an increase of 6 % , or $ 6,262. the increase was driven by royalties from higher oem production and sales to distributors , partially offset by lower direct to consumer sales . · 2014 vs. 2013 : for the years ended december 31 , 2014 and 2013 , equipment revenue was $ 104,661 and $ 80,573 , respectively , an increase of 30 % , or $ 24,088. the increase was driven by higher sales to distributors and royalties from oem production , partially offset by lower per unit revenue on direct to consumer sales . we expect equipment revenue to fluctuate based on oem production for which we receive royalty payments for our technology and , to a lesser extent , on the volume of equipment sales in our aftermarket and direct to consumer business . other revenue includes amounts earned from subscribers for the u.s. music royalty fee , revenue from our connected vehicle business and our canadian affiliate and ancillary revenues . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , other revenue was $ 512,050 and $ 421,150 , respectively , an increase of 22 % , or $ 90,900. the increase was driven by revenues from the u.s. music royalty fee as the number of subscribers subject to the 13.9 % rate increased along with an overall increase in subscribers , higher revenue generated from our connected vehicle business , and increased revenue from our canadian affiliate . story_separator_special_tag our annual effective tax rate for the year ended december 31 , 2013 was 40.8 % , primarily as a result of non-deductible expenses related to the loss on change in value of derivatives . key operating metrics in this section , we present certain financial and operating performance measures that are not calculated and presented in accordance with generally accepted accounting principles in the united states ( “ non-gaap ” ) . these metrics include : average monthly revenue per subscriber , or arpu ; customer service and billing expenses , per average subscriber ; subscriber acquisition cost , or sac , per installation ; free cash flow ; and adjusted ebitda . these measures exclude the impact of share-based payment expense and certain purchase price accounting adjustments related to the merger , which include the : ( i ) elimination of deferred revenue associated with the investment in xm canada , ( ii ) recognition of deferred subscriber revenues not recognized in purchase price accounting , and ( iii ) elimination of the benefit of deferred credits on executory contracts , which are primarily attributable to third party arrangements with an oem and programming providers . additionally , when applicable , our adjusted ebitda and free cash flow metrics exclude the effect of any significant items that do not relate to the on-going performance of our business , such as settlements related to our historical use of pre-1972 sound recordings . we use these non-gaap financial measures to manage our business , to set operational goals and as a basis for determining performance-based compensation for our employees . free cash flow is a metric that our management and board of directors use to evaluate the cash generated by our operations , net of capital expenditures and other investment activity and significant items that do not relate to the on-going performance of our business . in a capital intensive business , with significant investments in satellites , we look at our operating cash flow , net of these investing cash outflows , to determine cash available for future subscriber acquisition and capital expenditures , to repurchase or retire debt , to acquire other companies and to evaluate our ability to return capital to stockholders . we believe free cash flow is an indicator of the long-term financial stability of our business . free cash flow , which is reconciled to “ net cash provided by operating activities , ” is a non-gaap financial measure . this measure can be calculated by deducting amounts under the captions “ additions to property and equipment ” , deducting or adding restricted and other investment activity and the return of capital from investment in unconsolidated entity from “ net cash provided by operating activities ” from the consolidated statements of cash flows , adjusted for any significant legal settlements . free cash flow should be used in conjunction with other gaap financial performance measures and may not be comparable to free cash flow measures presented by other companies . free cash flow should be viewed as a supplemental measure rather than an alternative measure of cash flows from operating activities , as determined in accordance with gaap . free cash flow is limited and does not represent remaining cash flows available for discretionary expenditures due to the fact that the measure does not deduct the payments required for debt maturities . we believe free cash flow provides useful supplemental information to investors regarding our current and projected cash flow , along with other gaap measures ( such as cash flows from operating and investing activities ) , to determine our financial condition , and to compare our operating performance to other communications , entertainment and media companies . we have excluded the $ 210,000 payment related to the pre-1972 sound recordings legal settlement from our free cash flow calculation in the year ended december 31 , 2015. we believe these non-gaap financial measures provide useful information to investors regarding our financial condition and results of operations . we believe investors find these non-gaap financial performance measures useful in evaluating our core trends because it provides a direct view of our underlying contractual costs . we believe investors use our current and projected adjusted ebitda to estimate our current or prospective enterprise value and to make investment decisions . by providing these non-gaap financial measures , together with the reconciliations to the most directly comparable gaap measure , we believe we are enhancing investors ' understanding of our business and our results of operations . 29 these non-gaap financial measures should be viewed in addition to , and not as an alternative for or superior to , our reported results prepared in accordance with gaap . in addition , these non-gaap financial measures may not be comparable to sim ilarly-titled measures by other companies . please refer to the glossary ( pages 36 through 40 ) for a further discussion of such non-gaap financial measures and reconciliations to the most directly comparable gaap measure . the following table contains our key operating metrics based on our adjusted results of operations for the years ended december 31 , 2015 , 2014 and 2013 . subscribers and subscription related revenues and expenses associated with our connected vehicle services are not included in our subscr iber count or subscriber-based operating metrics : replace_table_token_5_th ( a ) note : amounts may not sum as a result of rounding . subscribers . at december 31 , 2015 , we had approximately 29.6 million subscribers , an increase of approximately 2.3 million subscribers , or 8 % , from the approximate 27.3 million subscribers as of december 31 , 2014 . · 2015 vs. 2014 : for the years ended december 31 , 2015 and 2014 , net additions were 2,283 thousand and 1,752 thousand , respectively , an increase of 30 % , or 531 thousand . the increase in subscribers was primarily due to increases in original and

