in summary , our cash flows for each period were as follows: .
in 2013 what was the approximate percentage increase in net cash provided by operating activities
operating activities cash provided by operating activities is net income adjusted for certain non-cash items and changes in certain assets and liabilities . for 2013 compared to 2012 , the $ 1.9 billion increase in cash provided by operating activities was due to changes in working capital , partially offset by lower net income in 2013 . income taxes paid , net of refunds , in 2013 compared to 2012 were $ 1.1 billion lower due to lower income before taxes in 2013 and 2012 income tax overpayments . changes in assets and liabilities as of december 28 , 2013 , compared to december 29 , 2012 , included lower income taxes payable and receivable resulting from a reduction in taxes due in 2013 , and lower inventories due to the sell-through of older-generation products , partially offset by the ramp of 4th generation intel core processor family products . for 2013 , our three largest customers accounted for 44% ( 44 % ) of our net revenue ( 43% ( 43 % ) in 2012 and 2011 ) , with hewlett- packard company accounting for 17% ( 17 % ) of our net revenue ( 18% ( 18 % ) in 2012 and 19% ( 19 % ) in 2011 ) , dell accounting for 15% ( 15 % ) of our net revenue ( 14% ( 14 % ) in 2012 and 15% ( 15 % ) in 2011 ) , and lenovo accounting for 12% ( 12 % ) of our net revenue ( 11% ( 11 % ) in 2012 and 9% ( 9 % ) in 2011 ) . these three customers accounted for 34% ( 34 % ) of our accounts receivable as of december 28 , 2013 ( 33% ( 33 % ) as of december 29 , 2012 ) . for 2012 compared to 2011 , the $ 2.1 billion decrease in cash provided by operating activities was due to lower net income and changes in our working capital , partially offset by adjustments for non-cash items . the adjustments for noncash items were higher due primarily to higher depreciation in 2012 compared to 2011 , partially offset by increases in non-acquisition-related deferred tax liabilities as of december 31 , 2011 . investing activities investing cash flows consist primarily of capital expenditures ; investment purchases , sales , maturities , and disposals ; as well as cash used for acquisitions . the increase in cash used for investing activities in 2013 compared to 2012 was primarily due to an increase in purchases of available-for-sale investments and a decrease in maturities and sales of trading assets , partially offset by an increase in maturities and sales of available-for-sale investments and a decrease in purchases of licensed technology and patents . our capital expenditures were $ 10.7 billion in 2013 ( $ 11.0 billion in 2012 and $ 10.8 billion in 2011 ) . cash used for investing activities increased in 2012 compared to 2011 primarily due to net purchases of available- for-sale investments and trading assets in 2012 , as compared to net maturities and sales of available-for-sale investments and trading assets in 2011 , partially offset by a decrease in cash paid for acquisitions . net purchases of available-for-sale investments in 2012 included our purchase of $ 3.2 billion of equity securities in asml in q3 2012 . financing activities financing cash flows consist primarily of repurchases of common stock , payment of dividends to stockholders , issuance and repayment of long-term debt , and proceeds from the sale of shares through employee equity incentive plans . table of contents management 2019s discussion and analysis of financial condition and results of operations ( continued ) .