the majority of revenue from our pandora business is generated from advertising on our pandora ad-supported radio service . in addition , through adswizz , pandora provides a comprehensive digital audio advertising technology platform , which connects audio publishers and advertisers . as of december 31 , 2019 , our pandora business had approximately 63.5 million monthly active users . liberty media as of december 31 , 2019 , liberty media beneficially owned , directly and indirectly , approximately 72 % of the outstanding shares of our common stock . as a result , we are a “ controlled company ” for the purposes of the nasdaq corporate governance requirements . 32 results of operations actual results set forth below are our results of operations for the year ended december 31 , 2019 compared with the year ended december 31 , 2018 and for the year ended december 31 , 2018 compared with the year ended december 31 , 2017 . the inclusion of pandora 's results in the year ended december 31 , 2019 ( since the date of the pandora acquisition on february 1 , 2019 ) may render direct comparisons with results for prior periods less meaningful . the results of operations are presented for each of our reporting segments for revenue and cost of services and on a consolidated basis for all other items . replace_table_token_3_th 33 nm - not meaningful sirius xm revenue refer to page 38 for our discussion on sirius xm revenue . pandora revenue pandora revenue includes actual results for the period from the acquisition date to december 31 , 2019. refer to page 40 for our discussion on pandora revenue . sirius xm cost of services refer to page 40 for our discussion on sirius xm cost of services . pandora cost of services pandora cost of services includes actual results for the period from the acquisition date to december 31 , 2019. refer to page 42 for our discussion on pandora cost of services . operating costs subscriber acquisition costs are costs associated with our satellite radio service and include hardware subsidies paid to radio manufacturers , distributors and automakers ; subsidies paid for chipsets and certain other components used in manufacturing radios ; device royalties for certain radios and chipsets ; product warranty obligations ; and freight . the majority of subscriber acquisition costs are incurred and expensed in advance of acquiring a subscriber . subscriber acquisition costs do not include advertising costs , marketing , loyalty payments to distributors and dealers of satellite radios or revenue share payments to automakers and retailers of satellite radios . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , subscriber acquisition costs were $ 427 and $ 470 , respectively , a decrease of 9 % , or $ 43 , and decreased as a percentage of total revenue . the decrease was driven by reductions to oem hardware subsidy rates , lower subsidized costs related to the transition of chipsets , and a decrease in the volume of satellite radio installations . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , subscriber acquisition costs were $ 470 and $ 499 , respectively , a decrease of 6 % , or $ 29 , and decreased as a percentage of total revenue . the decrease was driven by reductions to oem hardware subsidy rates , lower subsidized costs related to the transition of chipsets , and a decrease in the volume of satellite radio installations . we expect subscriber acquisition costs to fluctuate with oem installations ; however , the subsidized chipsets cost is expected to decline as we transition to a new generation of chipsets . we intend to continue to offer subsidies and other incentives to induce oems to include our technology in their vehicles . sales and marketing includes costs for marketing , advertising , media and production , including promotional events and sponsorships ; cooperative and artist marketing ; and personnel related costs including salaries , commissions , and sales support . marketing costs include expenses related to direct mail , outbound telemarketing , email communications , and digital performance media . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , sales and marketing expenses were $ 937 and $ 484 , respectively , an increase of 94 % , or $ 453 , and increased as a percentage of total revenue . the increase was primarily due to the inclusion of pandora , and additional subscriber communications and acquisition campaigns . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , sales and marketing expenses were $ 484 and $ 438 , respectively , an increase of 11 % , or $ 46 , and increased as a percentage of total revenue . the increase was primarily due to additional subscriber communications , retention programs and acquisition campaigns as well as higher personnel-related costs . 34 we anticipate that sales and marketing expenses will increase as we expand programs to retain our existing subscribers , win back former subscribers , and attract new subscribers . engineering , design and development consists primarily of compensation and related costs to develop chipsets and new products and services , including streaming and connected vehicle services , research and development for broadcast information systems and the design and development costs to incorporate sirius xm radios into new vehicles manufactured by automakers . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , engineering , design and development expenses were $ 280 and $ 123 , respectively , an increase of 128 % , or $ 157 , and increased as a percentage of total revenue . the increase was driven primarily by the inclusion of pandora . story_separator_special_tag total consolidated revenue total consolidated revenue for the years ended december 31 , 2019 and 2018 , was $ 7,921 and $ 7,348 , respectively , an increase of 8 % , or $ 573 . total consolidated revenue for the years ended december 31 , 2018 and 2017 , was $ 7,348 and $ 6,818 , respectively , an increase of 8 % , or $ 530 . sirius xm cost of services sirius xm cost of services includes revenue share and royalties , programming and content , customer service and billing and transmission expenses . sirius xm revenue share and royalties include royalties for transmitting content , including streaming royalties , as well as automaker , content provider and advertising revenue share . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , revenue share and royalties were $ 1,431 and $ 1,394 , respectively , an increase of 3 % , or $ 37 , but decreased as a percentage of total sirius xm revenue . the increase was driven by overall greater revenues subject to royalties and revenue share . the increase was partially offset by a $ 69 charge during the second quarter of 2018 related to the legal settlement that resolved all outstanding claims , including ongoing audits , under sirius xm 's statutory license for sound recordings for the period january 1 , 2007 through december 31 , 2017 . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , revenue share and royalties were $ 1,394 and $ 1,210 , respectively , an increase of 15 % , or $ 184 , and increased as a percentage of total sirius xm revenue . the increase was driven by an increase in the statutory royalty rate applicable to our use of post-1972 recordings , which increased from 11 % in 2017 to 15.5 % in 2018 , and overall greater revenues subject to revenue share with the automakers . included in the increase was a $ 69 charge related to the legal settlement that resolved outstanding claims , including ongoing audits , under our statutory license for sound recordings for the period january 1 , 2007 through december 31 , 2017. in 2017 , we recorded $ 45 of expense related to music royalty legal settlements and related reserves . the increase was partially offset by approximately $ 88 for the year ended december 31 , 2018 , related to the adoption of asu 2014‑09 , which established accounting standard codification ( asc ) topic 606 , revenue ‑ revenue from contracts with customers , effective as of january 1 , 2018 . 40 we expect our sirius xm revenue share and royalty costs to increase as our revenues grow . sirius xm programming and content includes costs to acquire , create , promote and produce content . we have entered into various agreements with third parties for music and non-music programming that require us to pay license fees and other amounts . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , programming and content expenses were $ 444 and $ 406 , respectively , an increase of 9 % , or $ 38 , and increased as a percentage of total sirius xm revenue . the increase was primarily driven by higher content licensing costs as well as greater personnel-related costs . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , programming and content expenses were $ 406 and $ 388 , respectively , an increase of 5 % , or $ 18 , but decreased as a percentage of total sirius xm revenue . the increase was driven primarily by personnel-related costs , and higher music licensing costs . we expect our sirius xm programming and content expenses to increase as we offer additional programming and renew or replace expiring agreements . sirius xm customer service and billing includes costs associated with the operation and management of internal and third party customer service centers , and our subscriber management systems as well as billing and collection costs , bad debt expense , and transaction fees . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , customer service and billing expenses were $ 398 and $ 382 , respectively , an increase of 4 % , or $ 16 , but decreased as a percentage of total sirius xm revenue . the increase was driven by increased transaction fees from a larger subscriber base and higher bad debt expense . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , customer service and billing expenses were $ 382 and $ 385 , respectively , a decrease of 1 % , or $ 3 , and decreased as a percentage of total sirius xm revenue . the decrease was primarily driven by lower call center costs due to lower agent rates , increased customer self-service and improved non-pay processes driving lower bad debt expense , partially offset by increased transaction fees from a larger subscriber base and personnel-related costs . we expect our sirius xm customer service and billing expenses to increase as our subscriber base grows . sirius xm transmission consists of costs associated with the operation and maintenance of our terrestrial repeater networks ; satellites ; satellite telemetry , tracking and control systems ; satellite uplink facilities ; studios ; and delivery of our internet streaming and connected vehicle services . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , transmission expenses were $ 112 and $ 96 , respectively , an increase of 17 % , or $ 16 , and increased as a percentage of total sirius xm revenue . the increase was primarily driven by higher cloud hosting and costs associated with our streaming services and higher repeater network

cash flows for the year ended december 31 , 2019 compared with the year ended december 31 , 2018 and for the year ended december 31 , 2018 compared with the year ended december 31 , 2017 . the following table presents a summary of our cash flow activity for the periods set forth below : replace_table_token_10_th cash flows provided by operating activities cash flows provided by operating activities increased by $ 137 to $ 2,017 for the year ended december 31 , 2019 from $ 1,880 for the year ended december 31 , 2018 . cash flows provided by operating activities increased by $ 24 to $ 1,880 for the year ended december 31 , 2018 from $ 1,856 for the year ended december 31 , 2017 . our largest source of cash provided by operating activities is cash generated by subscription and subscription-related revenues . we also generate cash from the sale of advertising on pandora , advertising on certain non-music channels on sirius xm and the sale of satellite radios , components and accessories . our primary uses of cash from operating activities include revenue share and royalty payments to distributors , programming and content providers , and payments to radio manufacturers , distributors and automakers . in addition , uses of cash from operating activities include payments to vendors to service , maintain and acquire listeners and subscribers , general corporate expenditures , and compensation and related costs .


 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.
     ```cash flows for the year ended december 31 , 2019 compared with the year ended december 31 , 2018 and for the year ended december 31 , 2018 compared with the year ended december 31 , 2017 . the following table presents a summary of our cash flow activity for the periods set forth below : replace_table_token_10_th cash flows provided by operating activities cash flows provided by operating activities increased by $ 137 to $ 2,017 for the year ended december 31 , 2019 from $ 1,880 for the year ended december 31 , 2018 . cash flows provided by operating activities increased by $ 24 to $ 1,880 for the year ended december 31 , 2018 from $ 1,856 for the year ended december 31 , 2017 . our largest source of cash provided by operating activities is cash generated by subscription and subscription-related revenues . we also generate cash from the sale of advertising on pandora , advertising on certain non-music channels on sirius xm and the sale of satellite radios , components and accessories . our primary uses of cash from operating activities include revenue share and royalty payments to distributors , programming and content providers , and payments to radio manufacturers , distributors and automakers . in addition , uses of cash from operating activities include payments to vendors to service , maintain and acquire listeners and subscribers , general corporate expenditures , and compensation and related costs .
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 Suspicious Activity Report : the majority of revenue from our pandora business is generated from advertising on our pandora ad-supported radio service . in addition , through adswizz , pandora provides a comprehensive digital audio advertising technology platform , which connects audio publishers and advertisers . as of december 31 , 2019 , our pandora business had approximately 63.5 million monthly active users . liberty media as of december 31 , 2019 , liberty media beneficially owned , directly and indirectly , approximately 72 % of the outstanding shares of our common stock . as a result , we are a “ controlled company ” for the purposes of the nasdaq corporate governance requirements . 32 results of operations actual results set forth below are our results of operations for the year ended december 31 , 2019 compared with the year ended december 31 , 2018 and for the year ended december 31 , 2018 compared with the year ended december 31 , 2017 . the inclusion of pandora 's results in the year ended december 31 , 2019 ( since the date of the pandora acquisition on february 1 , 2019 ) may render direct comparisons with results for prior periods less meaningful . the results of operations are presented for each of our reporting segments for revenue and cost of services and on a consolidated basis for all other items . replace_table_token_3_th 33 nm - not meaningful sirius xm revenue refer to page 38 for our discussion on sirius xm revenue . pandora revenue pandora revenue includes actual results for the period from the acquisition date to december 31 , 2019. refer to page 40 for our discussion on pandora revenue . sirius xm cost of services refer to page 40 for our discussion on sirius xm cost of services . pandora cost of services pandora cost of services includes actual results for the period from the acquisition date to december 31 , 2019. refer to page 42 for our discussion on pandora cost of services . operating costs subscriber acquisition costs are costs associated with our satellite radio service and include hardware subsidies paid to radio manufacturers , distributors and automakers ; subsidies paid for chipsets and certain other components used in manufacturing radios ; device royalties for certain radios and chipsets ; product warranty obligations ; and freight . the majority of subscriber acquisition costs are incurred and expensed in advance of acquiring a subscriber . subscriber acquisition costs do not include advertising costs , marketing , loyalty payments to distributors and dealers of satellite radios or revenue share payments to automakers and retailers of satellite radios . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , subscriber acquisition costs were $ 427 and $ 470 , respectively , a decrease of 9 % , or $ 43 , and decreased as a percentage of total revenue . the decrease was driven by reductions to oem hardware subsidy rates , lower subsidized costs related to the transition of chipsets , and a decrease in the volume of satellite radio installations . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , subscriber acquisition costs were $ 470 and $ 499 , respectively , a decrease of 6 % , or $ 29 , and decreased as a percentage of total revenue . the decrease was driven by reductions to oem hardware subsidy rates , lower subsidized costs related to the transition of chipsets , and a decrease in the volume of satellite radio installations . we expect subscriber acquisition costs to fluctuate with oem installations ; however , the subsidized chipsets cost is expected to decline as we transition to a new generation of chipsets . we intend to continue to offer subsidies and other incentives to induce oems to include our technology in their vehicles . sales and marketing includes costs for marketing , advertising , media and production , including promotional events and sponsorships ; cooperative and artist marketing ; and personnel related costs including salaries , commissions , and sales support . marketing costs include expenses related to direct mail , outbound telemarketing , email communications , and digital performance media . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , sales and marketing expenses were $ 937 and $ 484 , respectively , an increase of 94 % , or $ 453 , and increased as a percentage of total revenue . the increase was primarily due to the inclusion of pandora , and additional subscriber communications and acquisition campaigns . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , sales and marketing expenses were $ 484 and $ 438 , respectively , an increase of 11 % , or $ 46 , and increased as a percentage of total revenue . the increase was primarily due to additional subscriber communications , retention programs and acquisition campaigns as well as higher personnel-related costs . 34 we anticipate that sales and marketing expenses will increase as we expand programs to retain our existing subscribers , win back former subscribers , and attract new subscribers . engineering , design and development consists primarily of compensation and related costs to develop chipsets and new products and services , including streaming and connected vehicle services , research and development for broadcast information systems and the design and development costs to incorporate sirius xm radios into new vehicles manufactured by automakers . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , engineering , design and development expenses were $ 280 and $ 123 , respectively , an increase of 128 % , or $ 157 , and increased as a percentage of total revenue . the increase was driven primarily by the inclusion of pandora . story_separator_special_tag total consolidated revenue total consolidated revenue for the years ended december 31 , 2019 and 2018 , was $ 7,921 and $ 7,348 , respectively , an increase of 8 % , or $ 573 . total consolidated revenue for the years ended december 31 , 2018 and 2017 , was $ 7,348 and $ 6,818 , respectively , an increase of 8 % , or $ 530 . sirius xm cost of services sirius xm cost of services includes revenue share and royalties , programming and content , customer service and billing and transmission expenses . sirius xm revenue share and royalties include royalties for transmitting content , including streaming royalties , as well as automaker , content provider and advertising revenue share . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , revenue share and royalties were $ 1,431 and $ 1,394 , respectively , an increase of 3 % , or $ 37 , but decreased as a percentage of total sirius xm revenue . the increase was driven by overall greater revenues subject to royalties and revenue share . the increase was partially offset by a $ 69 charge during the second quarter of 2018 related to the legal settlement that resolved all outstanding claims , including ongoing audits , under sirius xm 's statutory license for sound recordings for the period january 1 , 2007 through december 31 , 2017 . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , revenue share and royalties were $ 1,394 and $ 1,210 , respectively , an increase of 15 % , or $ 184 , and increased as a percentage of total sirius xm revenue . the increase was driven by an increase in the statutory royalty rate applicable to our use of post-1972 recordings , which increased from 11 % in 2017 to 15.5 % in 2018 , and overall greater revenues subject to revenue share with the automakers . included in the increase was a $ 69 charge related to the legal settlement that resolved outstanding claims , including ongoing audits , under our statutory license for sound recordings for the period january 1 , 2007 through december 31 , 2017. in 2017 , we recorded $ 45 of expense related to music royalty legal settlements and related reserves . the increase was partially offset by approximately $ 88 for the year ended december 31 , 2018 , related to the adoption of asu 2014‑09 , which established accounting standard codification ( asc ) topic 606 , revenue ‑ revenue from contracts with customers , effective as of january 1 , 2018 . 40 we expect our sirius xm revenue share and royalty costs to increase as our revenues grow . sirius xm programming and content includes costs to acquire , create , promote and produce content . we have entered into various agreements with third parties for music and non-music programming that require us to pay license fees and other amounts . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , programming and content expenses were $ 444 and $ 406 , respectively , an increase of 9 % , or $ 38 , and increased as a percentage of total sirius xm revenue . the increase was primarily driven by higher content licensing costs as well as greater personnel-related costs . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , programming and content expenses were $ 406 and $ 388 , respectively , an increase of 5 % , or $ 18 , but decreased as a percentage of total sirius xm revenue . the increase was driven primarily by personnel-related costs , and higher music licensing costs . we expect our sirius xm programming and content expenses to increase as we offer additional programming and renew or replace expiring agreements . sirius xm customer service and billing includes costs associated with the operation and management of internal and third party customer service centers , and our subscriber management systems as well as billing and collection costs , bad debt expense , and transaction fees . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , customer service and billing expenses were $ 398 and $ 382 , respectively , an increase of 4 % , or $ 16 , but decreased as a percentage of total sirius xm revenue . the increase was driven by increased transaction fees from a larger subscriber base and higher bad debt expense . 2018 vs. 2017 : for the years ended december 31 , 2018 and 2017 , customer service and billing expenses were $ 382 and $ 385 , respectively , a decrease of 1 % , or $ 3 , and decreased as a percentage of total sirius xm revenue . the decrease was primarily driven by lower call center costs due to lower agent rates , increased customer self-service and improved non-pay processes driving lower bad debt expense , partially offset by increased transaction fees from a larger subscriber base and personnel-related costs . we expect our sirius xm customer service and billing expenses to increase as our subscriber base grows . sirius xm transmission consists of costs associated with the operation and maintenance of our terrestrial repeater networks ; satellites ; satellite telemetry , tracking and control systems ; satellite uplink facilities ; studios ; and delivery of our internet streaming and connected vehicle services . 2019 vs. 2018 : for the years ended december 31 , 2019 and 2018 , transmission expenses were $ 112 and $ 96 , respectively , an increase of 17 % , or $ 16 , and increased as a percentage of total sirius xm revenue . the increase was primarily driven by higher cloud hosting and costs associated with our streaming services and higher repeater network

