many of our current contracts include clinical trials covering multiple geographic locations . we utilize the same management systems and reporting tools to monitor and manage these activities on the same basis worldwide . for this reason , we consider our operations to be a single business segment , and we present our results of operations as a single reportable segment . 41 our gross new business awards for the years ended december 31 , 2016 , 2015 and 2014 were $ 2,367.1 million , $ 1,927.6 million and $ 1,745.4 million , respectively . new business awards arise when a client selects us to execute its trial and is documented by written or electronic correspondence or for our strategic solutions offering when the amount of revenue expected to be recognized is measurable . the number of new business awards can vary significantly from year to year , and awards can have terms ranging from several months to several years . for our strategic solutions offering , the value of a new business award is the anticipated service revenue to be recognized in the corresponding quarter of the next fiscal year . for the remainder of our business , the value of a new award is the anticipated service revenue over the life of the contract , which does not include reimbursement activity or investigator fees . in the normal course of business , we experience contract cancellations , which are reflected as cancellations when the client provides us with written or electronic correspondence that the work should cease . during the years ended december 31 , 2016 , 2015 and 2014 we had $ 290.6 million , $ 231.0 million , and $ 251.7 million , respectively , of cancellations for which we received correspondence from the client . the number of cancellations can vary significantly from year to year . the value of the cancellation is the remaining amount of unrecognized service revenue , less the estimated effort to transition the work back to the client . our backlog consists of anticipated service revenue from new business awards that either have not started or are in process but have not been completed . backlog varies from period to period depending upon new business awards and contract modifications , cancellations , and the amount of service revenue recognized under existing contracts . our backlog at december 31 , 2016 , 2015 and 2014 was $ 2.9 billion , $ 2.4 billion , and $ 2.1 billion , respectively . industry trends isr estimated in its isr 2016 market report that the size of the worldwide cro market was approximately $ 28 billion in 2015 and will grow at a 7 % cagr to $ 38 billion over the next five years . this growth will be driven by an increase in the amount of research and development expenditures and higher levels of clinical development outsourcing by biopharmaceutical companies . acquisition of pra by kohlberg kravis roberts & co. l.p. on september 23 , 2013 , we were acquired by affiliates of kkr for $ 1.4 billion pursuant to a plan of merger by and among the company , merger sub and genstar , or merger . upon completion of the kkr transaction , merger sub was merged with and into pra holdings , inc. , predecessor company , which became a subsidiary of pinnacle holdco parent , inc. , or parent . on december 19 , 2013 , pinnacle holdco parent , inc. changed its name to pra global holdings , inc. and on july 10 , 2014 , pra global holdings , inc. changed its name to pra health sciences , inc. business combinations we have completed a number of acquisitions during 2015 and 2016 to enhance our capabilities and service offerings in certain areas . on june 8 , 2015 , we purchased the assets of value health solutions inc. , or vhs , a software development firm , for $ 0.5 million in cash and 47,598 unregistered shares of our common stock with a fair market value of $ 1.6 million ; an additional $ 0.4 million of common stock will be issued in june 2017 , less amounts reimbursable to us for any indemnification obligations of the seller . the asset purchase agreement also includes contingent consideration in the form of potential earn-out payments of up to $ 16.0 million . on march 18 , 2016 , we acquired all of the outstanding shares of nextrials , inc. , or nextrials , a developer of web-based software which integrates electronic health records with clinical trials , for $ 4.8 million in cash and contingent consideration in the form of potential earn-out payments of up to $ 3.0 million . on may 6 , 2016 , as part of the dissolution of the wuxipra clinical research ( shanghai ) co. , ltd. joint venture , or wuxipra , we acquired wuxipra 's hong kong operations for $ 0.3 million . the results of operations of acquired businesses have been included since the date of acquisition . 42 see note 4 to our audited consolidated financial statements found elsewhere in this annual report on form 10-k for additional information with respect to the acquisitions . joint ventures on may 6 , 2016 , we and wuxi apptec ( shanghai ) co. , ltd. , or wuxi , finalized an agreement to dissolve the wuxipra joint venture . under the agreement , we sold our 49 % portion of the joint venture located in mainland china for $ 4.0 million , which subsequently became a wholly owned subsidiary of wuxi . the portion of the joint venture located in hong kong became our wholly owned subsidiary and was acquired for $ 0.3 million . story_separator_special_tag the growth in service revenue and the increase in billable hours were due largely to the increase in our backlog as we entered the year , the type of services we are providing on our active studies , which was driven by the life cycles of projects that were active during the period , the growth in new business awards as a result of higher demand for our services across the industries we serve , and more effective sales efforts and the growth in the overall cro market . new business awards arise when a client selects us to execute its trial . the number of awards can vary significantly from period to period and our studies have terms ranging from several months to several years . the increase in our effective rate of the hours billed on our studies is attributable to the contract pricing terms on our current mix of active studies and the mix of clients and the services that we provide to those clients . direct costs increased by $ 146.2 million , or 16.5 % , from $ 886.5 million during the year ended december 31 , 2015 to $ 1,032.7 million during the year ended december 31 , 2016. the increase in direct costs was primarily due to an increase in labor-related costs of $ 170.6 million , as we continued to hire billable staff to support our current projects and as we hired additional staff in anticipation of our growing portfolio of studies , offset by a favorable impact of $ 21.3 million from foreign currency exchange rate fluctuations . direct costs as a percentage of service revenue increased from 64.4 % during the year ended december 31 , 2015 to 65.4 % during the year ended december 31 , 2016. this increase in direct costs as a percentage of service revenue is primarily due to the $ 8.3 million impact of research and development credits , or r & d credits , recorded during the year ended december 31 , 2015 that related to prior years . the r & d credits are the result of a comprehensive analysis we have been performing across the organization to determine whether expenditures incurred qualify as research and development as defined by the respective jurisdiction . selling , general and administrative expenses increased by $ 23.5 million , or 9.5 % , from $ 246.4 million during the year ended december 31 , 2015 to $ 269.9 million during the year ended december 31 , 2016. selling , general and administrative expenses as a percentage of service revenue decreased from 17.9 % during the year ended december 31 , 2015 to 17.1 % during the year ended december 31 , 2016. this decrease in selling , general and 47 administrative expenses as a percentage of service revenue is primarily related to our continued efforts to effectively manage our selling and administrative functions as we continue to grow . during the year ended december 31 , 2016 , we incurred transaction-related expenses of $ 44.8 million . the costs consist of $ 10.1 million of stock-based compensation expense associated with the release of the transfer restrictions on a portion of shares issuable upon exercise of vested service-based options in connection with the announcement of our march , may , and november 2016 secondary offerings . the costs also include $ 32.0 million of stock-based compensation expense related to the vesting and release of the transfer restrictions of certain performance-based stock options . in addition , we incurred $ 2.7 million of third-party fees associated with the secondary offerings and the closing of our accounts receivable financing agreement . there were no transaction-related expenses incurred for the year ended december 31 , 2015. depreciation and amortization expense decreased by $ 8.4 million , or 10.8 % , from $ 78.0 million during the year ended december 31 , 2015 to $ 69.5 million during the year ended december 31 , 2016. depreciation and amortization expense as a percentage of service revenue was 5.7 % during the year ended december 31 , 2015 and 4.4 % during the year ended december 31 , 2016. the decrease in depreciation and amortization expense as a percentage of service revenue is primarily due the continued decline in amortization of our acquired intangibles , which are amortized on an accelerated basis . interest expense , net decreased by $ 6.8 million from $ 61.7 million during the year ended december 31 , 2015 to $ 54.9 million during the year ended december 31 , 2016. the cash tender on our senior notes during 2016 , as well as a 0.8 % decrease in the weighted average interest rate on our outstanding debt as compared to the year ended december 31 , 2015 , resulted in a $ 9.7 million reduction in interest expense . additionally , interest expense decreased $ 1.6 million due to lower amortization of debt issuance costs , which was offset by an increase of $ 4.7 million related to the amortization of our terminated interest rate swaps and interest expense on our current interest rate swap . losses on modification or extinguishment of debt were $ 38.2 million during the year ended december 31 , 2016 and there were no losses on modification of debt during the year ended december 31 , 2015. the $ 38.2 million loss on extinguishment of debt incurred during the year ended december 31 , 2016 was associated with our cash tender offer on our senior notes and our refinancing of the 2013 credit facilities . the loss of $ 21.5 million due to our cash tender offer consisted of a $ 17.4 million early tender premium , a $ 3.7 million write-off of unamortized debt issuance cost and $ 0.4 million of fees associated with the transaction . the refinancing of our 2013 credit facilities resulted in a $ 16.7 million loss on extinguishment of debt , which consisted of the write-off

cash flow from operating activities cash provided by operating activities increased by $ 7.6 million during the year ended december 31 , 2016 as compared to 2015. the increase in operating cash flow reflects increased cash flows from our operating performance and a reduction in interest payments , which was partially offset by an increase in cash outflows primarily from working capital . the changes in working capital were driven by a $ 2.1 million decrease in accounts payable and accrued expenses during the year ended december 31 , 2016 as compared to $ 21.3 million increase during the year ended december 31 , 2015 and is attributable to the timing and payment of invoices . this is partially offset by a $ 9.1 million improvement in cash outflows from our accounts receivable , unbilled services , and advanced billings accounts , driven by a slower rate of increase in our days sales outstanding during the year ended december 31 , 2016. cash provided by operating activities increased by $ 118.4 million during the year ended december 31 , 2015 as compared to 2014. the increase in operating cash flow reflects an increase in net income , a reduction in interest payments , as well as reduction in cash outflows from working capital . interest payments decreased by $ 26.1 million , primarily due to the debt payments made in conjunction with the ipo during november 2014. additionally , net income for the year ended december 31 , 2014 included a $ 11.9 million fee paid to terminate our monitoring agreement with kkr . dso contributed to a $ 31.3 million improvement in cash flow from operations and reflects a slower rate of increase in our dso in 2015 as compared to 2014. dso can shift significantly at each reporting period depending on the timing of cash receipts under contractual payment terms relative to the recognition of revenue over a project lifecycle .


 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 flow from operating activities cash provided by operating activities increased by $ 7.6 million during the year ended december 31 , 2016 as compared to 2015. the increase in operating cash flow reflects increased cash flows from our operating performance and a reduction in interest payments , which was partially offset by an increase in cash outflows primarily from working capital . the changes in working capital were driven by a $ 2.1 million decrease in accounts payable and accrued expenses during the year ended december 31 , 2016 as compared to $ 21.3 million increase during the year ended december 31 , 2015 and is attributable to the timing and payment of invoices . this is partially offset by a $ 9.1 million improvement in cash outflows from our accounts receivable , unbilled services , and advanced billings accounts , driven by a slower rate of increase in our days sales outstanding during the year ended december 31 , 2016. cash provided by operating activities increased by $ 118.4 million during the year ended december 31 , 2015 as compared to 2014. the increase in operating cash flow reflects an increase in net income , a reduction in interest payments , as well as reduction in cash outflows from working capital . interest payments decreased by $ 26.1 million , primarily due to the debt payments made in conjunction with the ipo during november 2014. additionally , net income for the year ended december 31 , 2014 included a $ 11.9 million fee paid to terminate our monitoring agreement with kkr . dso contributed to a $ 31.3 million improvement in cash flow from operations and reflects a slower rate of increase in our dso in 2015 as compared to 2014. dso can shift significantly at each reporting period depending on the timing of cash receipts under contractual payment terms relative to the recognition of revenue over a project lifecycle .
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 Suspicious Activity Report : many of our current contracts include clinical trials covering multiple geographic locations . we utilize the same management systems and reporting tools to monitor and manage these activities on the same basis worldwide . for this reason , we consider our operations to be a single business segment , and we present our results of operations as a single reportable segment . 41 our gross new business awards for the years ended december 31 , 2016 , 2015 and 2014 were $ 2,367.1 million , $ 1,927.6 million and $ 1,745.4 million , respectively . new business awards arise when a client selects us to execute its trial and is documented by written or electronic correspondence or for our strategic solutions offering when the amount of revenue expected to be recognized is measurable . the number of new business awards can vary significantly from year to year , and awards can have terms ranging from several months to several years . for our strategic solutions offering , the value of a new business award is the anticipated service revenue to be recognized in the corresponding quarter of the next fiscal year . for the remainder of our business , the value of a new award is the anticipated service revenue over the life of the contract , which does not include reimbursement activity or investigator fees . in the normal course of business , we experience contract cancellations , which are reflected as cancellations when the client provides us with written or electronic correspondence that the work should cease . during the years ended december 31 , 2016 , 2015 and 2014 we had $ 290.6 million , $ 231.0 million , and $ 251.7 million , respectively , of cancellations for which we received correspondence from the client . the number of cancellations can vary significantly from year to year . the value of the cancellation is the remaining amount of unrecognized service revenue , less the estimated effort to transition the work back to the client . our backlog consists of anticipated service revenue from new business awards that either have not started or are in process but have not been completed . backlog varies from period to period depending upon new business awards and contract modifications , cancellations , and the amount of service revenue recognized under existing contracts . our backlog at december 31 , 2016 , 2015 and 2014 was $ 2.9 billion , $ 2.4 billion , and $ 2.1 billion , respectively . industry trends isr estimated in its isr 2016 market report that the size of the worldwide cro market was approximately $ 28 billion in 2015 and will grow at a 7 % cagr to $ 38 billion over the next five years . this growth will be driven by an increase in the amount of research and development expenditures and higher levels of clinical development outsourcing by biopharmaceutical companies . acquisition of pra by kohlberg kravis roberts & co. l.p. on september 23 , 2013 , we were acquired by affiliates of kkr for $ 1.4 billion pursuant to a plan of merger by and among the company , merger sub and genstar , or merger . upon completion of the kkr transaction , merger sub was merged with and into pra holdings , inc. , predecessor company , which became a subsidiary of pinnacle holdco parent , inc. , or parent . on december 19 , 2013 , pinnacle holdco parent , inc. changed its name to pra global holdings , inc. and on july 10 , 2014 , pra global holdings , inc. changed its name to pra health sciences , inc. business combinations we have completed a number of acquisitions during 2015 and 2016 to enhance our capabilities and service offerings in certain areas . on june 8 , 2015 , we purchased the assets of value health solutions inc. , or vhs , a software development firm , for $ 0.5 million in cash and 47,598 unregistered shares of our common stock with a fair market value of $ 1.6 million ; an additional $ 0.4 million of common stock will be issued in june 2017 , less amounts reimbursable to us for any indemnification obligations of the seller . the asset purchase agreement also includes contingent consideration in the form of potential earn-out payments of up to $ 16.0 million . on march 18 , 2016 , we acquired all of the outstanding shares of nextrials , inc. , or nextrials , a developer of web-based software which integrates electronic health records with clinical trials , for $ 4.8 million in cash and contingent consideration in the form of potential earn-out payments of up to $ 3.0 million . on may 6 , 2016 , as part of the dissolution of the wuxipra clinical research ( shanghai ) co. , ltd. joint venture , or wuxipra , we acquired wuxipra 's hong kong operations for $ 0.3 million . the results of operations of acquired businesses have been included since the date of acquisition . 42 see note 4 to our audited consolidated financial statements found elsewhere in this annual report on form 10-k for additional information with respect to the acquisitions . joint ventures on may 6 , 2016 , we and wuxi apptec ( shanghai ) co. , ltd. , or wuxi , finalized an agreement to dissolve the wuxipra joint venture . under the agreement , we sold our 49 % portion of the joint venture located in mainland china for $ 4.0 million , which subsequently became a wholly owned subsidiary of wuxi . the portion of the joint venture located in hong kong became our wholly owned subsidiary and was acquired for $ 0.3 million . story_separator_special_tag the growth in service revenue and the increase in billable hours were due largely to the increase in our backlog as we entered the year , the type of services we are providing on our active studies , which was driven by the life cycles of projects that were active during the period , the growth in new business awards as a result of higher demand for our services across the industries we serve , and more effective sales efforts and the growth in the overall cro market . new business awards arise when a client selects us to execute its trial . the number of awards can vary significantly from period to period and our studies have terms ranging from several months to several years . the increase in our effective rate of the hours billed on our studies is attributable to the contract pricing terms on our current mix of active studies and the mix of clients and the services that we provide to those clients . direct costs increased by $ 146.2 million , or 16.5 % , from $ 886.5 million during the year ended december 31 , 2015 to $ 1,032.7 million during the year ended december 31 , 2016. the increase in direct costs was primarily due to an increase in labor-related costs of $ 170.6 million , as we continued to hire billable staff to support our current projects and as we hired additional staff in anticipation of our growing portfolio of studies , offset by a favorable impact of $ 21.3 million from foreign currency exchange rate fluctuations . direct costs as a percentage of service revenue increased from 64.4 % during the year ended december 31 , 2015 to 65.4 % during the year ended december 31 , 2016. this increase in direct costs as a percentage of service revenue is primarily due to the $ 8.3 million impact of research and development credits , or r & d credits , recorded during the year ended december 31 , 2015 that related to prior years . the r & d credits are the result of a comprehensive analysis we have been performing across the organization to determine whether expenditures incurred qualify as research and development as defined by the respective jurisdiction . selling , general and administrative expenses increased by $ 23.5 million , or 9.5 % , from $ 246.4 million during the year ended december 31 , 2015 to $ 269.9 million during the year ended december 31 , 2016. selling , general and administrative expenses as a percentage of service revenue decreased from 17.9 % during the year ended december 31 , 2015 to 17.1 % during the year ended december 31 , 2016. this decrease in selling , general and 47 administrative expenses as a percentage of service revenue is primarily related to our continued efforts to effectively manage our selling and administrative functions as we continue to grow . during the year ended december 31 , 2016 , we incurred transaction-related expenses of $ 44.8 million . the costs consist of $ 10.1 million of stock-based compensation expense associated with the release of the transfer restrictions on a portion of shares issuable upon exercise of vested service-based options in connection with the announcement of our march , may , and november 2016 secondary offerings . the costs also include $ 32.0 million of stock-based compensation expense related to the vesting and release of the transfer restrictions of certain performance-based stock options . in addition , we incurred $ 2.7 million of third-party fees associated with the secondary offerings and the closing of our accounts receivable financing agreement . there were no transaction-related expenses incurred for the year ended december 31 , 2015. depreciation and amortization expense decreased by $ 8.4 million , or 10.8 % , from $ 78.0 million during the year ended december 31 , 2015 to $ 69.5 million during the year ended december 31 , 2016. depreciation and amortization expense as a percentage of service revenue was 5.7 % during the year ended december 31 , 2015 and 4.4 % during the year ended december 31 , 2016. the decrease in depreciation and amortization expense as a percentage of service revenue is primarily due the continued decline in amortization of our acquired intangibles , which are amortized on an accelerated basis . interest expense , net decreased by $ 6.8 million from $ 61.7 million during the year ended december 31 , 2015 to $ 54.9 million during the year ended december 31 , 2016. the cash tender on our senior notes during 2016 , as well as a 0.8 % decrease in the weighted average interest rate on our outstanding debt as compared to the year ended december 31 , 2015 , resulted in a $ 9.7 million reduction in interest expense . additionally , interest expense decreased $ 1.6 million due to lower amortization of debt issuance costs , which was offset by an increase of $ 4.7 million related to the amortization of our terminated interest rate swaps and interest expense on our current interest rate swap . losses on modification or extinguishment of debt were $ 38.2 million during the year ended december 31 , 2016 and there were no losses on modification of debt during the year ended december 31 , 2015. the $ 38.2 million loss on extinguishment of debt incurred during the year ended december 31 , 2016 was associated with our cash tender offer on our senior notes and our refinancing of the 2013 credit facilities . the loss of $ 21.5 million due to our cash tender offer consisted of a $ 17.4 million early tender premium , a $ 3.7 million write-off of unamortized debt issuance cost and $ 0.4 million of fees associated with the transaction . the refinancing of our 2013 credit facilities resulted in a $ 16.7 million loss on extinguishment of debt , which consisted of the write-off

