Financial report context:
liquidity and capital resources as of december 31 , 2006 , our principal sources of liquidity included cash , cash equivalents , the sale of receivables , and our revolving credit facilities , as well as the availability of commercial paper and other sources of financing through the capital markets . we had $ 2 billion of committed credit facilities available , of which there were no borrowings outstanding as of december 31 , 2006 , and we did not make any short-term borrowings under these facilities during the year . the value of the outstanding undivided interest held by investors under the sale of receivables program was $ 600 million as of december 31 , 2006 . the sale of receivables program is subject to certain requirements , including the maintenance of an investment grade bond rating . if our bond rating were to deteriorate , it could have an adverse impact on our liquidity . access to commercial paper is dependent on market conditions . deterioration of our operating results or financial condition due to internal or external factors could negatively impact our ability to utilize commercial paper as a source of liquidity . liquidity through the capital markets is also dependent on our financial stability . at both december 31 , 2006 and 2005 , we had a working capital deficit of approximately $ 1.1 billion . a working capital deficit is common in our industry and does not indicate a lack of liquidity . we maintain adequate resources to meet our daily cash requirements , and we have sufficient financial capacity to satisfy our current liabilities . financial condition cash flows millions of dollars 2006 2005 2004 .

Financial table:
cash flowsmillions of dollars: cash provided by operating activities; 2006: $ 2880; 2005: $ 2595; 2004: $ 2257
cash flowsmillions of dollars: cash used in investing activities; 2006: -2042 ( 2042 ); 2005: -2047 ( 2047 ); 2004: -1732 ( 1732 )
cash flowsmillions of dollars: cash used in financing activities; 2006: -784 ( 784 ); 2005: -752 ( 752 ); 2004: -75 ( 75 )
cash flowsmillions of dollars: net change in cash and cash equivalents; 2006: $ 54; 2005: $ -204 ( 204 ); 2004: $ 450

Additional report context:
cash provided by operating activities 2013 higher income in 2006 generated the increased cash provided by operating activities , which was partially offset by higher income tax payments , $ 150 million in voluntary pension contributions , higher material and supply inventories , and higher management incentive payments in 2006 . higher income , lower management incentive payments in 2005 ( executive bonuses , which would have been paid to individuals in 2005 , were not awarded based on company performance in 2004 and bonuses for the professional workforce that were paid out in 2005 were significantly reduced ) , and working capital performance generated higher cash from operating activities in 2005 . a voluntary pension contribution of $ 100 million in 2004 also augmented the positive year-over-year variance in 2005 as no pension contribution was made in 2005 . this improvement was partially offset by cash received in 2004 for income tax refunds . cash used in investing activities 2013 an insurance settlement for the 2005 january west coast storm and lower balances for work in process decreased the amount of cash used in investing activities in 2006 . higher capital investments and lower proceeds from asset sales partially offset this decrease . increased capital spending , partially offset by higher proceeds from asset sales , increased the amount of cash used in investing activities in 2005 compared to 2004 . cash used in financing activities 2013 the increase in cash used in financing activities primarily resulted from lower net proceeds from equity compensation plans ( $ 189 million in 2006 compared to $ 262 million in 2005 ) . the increase in 2005 results from debt issuances in 2004 and higher debt repayments in 2005 . we did not issue debt in 2005 versus $ 745 million of debt issuances in 2004 , and we repaid $ 699 million of debt in 2005 compared to $ 588 million in 2004 . the higher outflows in 2005 were partially offset by higher net proceeds from equity compensation plans ( $ 262 million in 2005 compared to $ 80 million in 2004 ) . .

Question: what was the percentage change in cash provided by operating activities between 2004 and 2005?
Answer: 15%