management 2019s discussion and analysis of financial condition and results of operations 2013 ( continued ) ( amounts in millions , except per share amounts ) corporate and other expenses increased slightly during 2013 by $ 3.5 to $ 140.8 compared to 2012 , primarily due to an increase in salaries and related expenses , mainly attributable to higher base salaries , benefits and temporary help , partially offset by lower severance expenses and a decrease in office and general expenses . liquidity and capital resources cash flow overview the following tables summarize key financial data relating to our liquidity , capital resources and uses of capital. .
by how many percent did the net cash provided by operating activities increase 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 , 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 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 . 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 2014 was impacted by our media businesses . net cash provided by operating activities during 2013 was $ 592.9 , which was an increase of $ 235.7 as compared to 2012 , primarily as a result of an improvement in working capital usage of $ 283.6 , offset by a decrease in net income . the improvement in working capital in 2013 was impacted by our media businesses and an ongoing focus on working capital management at our agencies . 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 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. .