management 2019s discussion and analysis of financial condition and results of operations 2013 ( continued ) ( amounts in millions , except per share amounts ) liquidity and capital resources cash flow overview the following tables summarize key financial data relating to our liquidity , capital resources and uses of capital. .
what is the cash flow statement effect of the change in cash used for working capital from 2013 to 2014?
1 reflects net income adjusted primarily for depreciation and amortization of fixed assets and intangible assets , amortization of restricted stock and other non-cash compensation , non-cash ( gain ) loss related to early extinguishment of debt , losses on sales of businesses and deferred income taxes . 2 reflects changes in accounts receivable , expenditures billable to clients , other current assets , accounts payable and accrued liabilities . operating activities net cash provided by operating activities during 2015 was $ 674.0 , which was an improvement of $ 4.5 as compared to 2014 , primarily as a result of an improvement in working capital usage of $ 13.6 . due to the seasonality of our business , we typically generate cash from working capital in the second half of a year and use cash from working capital in the first half of a year , with the largest impacts in the first and fourth quarters . our net working capital usage in 2015 was primarily attributable to our media businesses . net cash provided by operating activities during 2014 was $ 669.5 , which was an improvement of $ 76.6 as compared to 2013 , primarily as a result of an increase in net income , offset by an increase in working capital usage of $ 121.5 . our net working capital usage in 2014 was impacted by our media businesses . the timing of media buying on behalf of our clients affects our working capital and operating cash flow . in most of our businesses , our agencies enter into commitments to pay production and media costs on behalf of clients . to the extent possible , we pay production and media charges after we have received funds from our clients . the amounts involved substantially exceed our revenues and primarily affect the level of accounts receivable , expenditures billable to clients , accounts payable and accrued liabilities . our assets include both cash received and accounts receivable from clients for these pass-through arrangements , while our liabilities include amounts owed on behalf of clients to media and production suppliers . our accrued liabilities are also affected by the timing of certain other payments . for example , while annual cash incentive awards are accrued throughout the year , they are generally paid during the first quarter of the subsequent year . investing activities net cash used in investing activities during 2015 primarily related to payments for capital expenditures of $ 161.1 , largely attributable to purchases of leasehold improvements and computer hardware . net cash used in investing activities during 2014 primarily related to payments for capital expenditures and acquisitions . capital expenditures of $ 148.7 related primarily to computer hardware and software and leasehold improvements . we made payments of $ 67.8 related to acquisitions completed during 2014 , net of cash acquired. .