no .159 requires that unrealized gains and losses on items for which the fair value option has been elected be reported in earnings at each reporting date .sfas no .159 is effective for fiscal years beginning after november 15 , 2007 and is required to be adopted by the company beginning in the first quarter of fiscal 2009 .although the company will continue to evaluate the application of sfas no .159 , management does not currently believe adoption will have a material impact on the company 2019s financial condition or operating results .in september 2006 , the fasb issued sfas no .157 , fair value measurements , which defines fair value , provides a framework for measuring fair value , and expands the disclosures required for fair value measurements .sfas no .157 applies to other accounting pronouncements that require fair value measurements ; it does not require any new fair value measurements .sfas no .157 is effective for fiscal years beginning after november 15 , 2007 and is required to be adopted by the company beginning in the first quarter of fiscal 2009 .although the company will continue to evaluate the application of sfas no .157 , management does not currently believe adoption will have a material impact on the company 2019s financial condition or operating results .in june 2006 , the fasb issued fasb interpretation no .( 2018 2018fin 2019 2019 ) 48 , accounting for uncertainty in income taxes-an interpretation of fasb statement no .109 .fin 48 clarifies the accounting for uncertainty in income taxes by creating a framework for how companies should recognize , measure , present , and disclose in their financial statements uncertain tax positions that they have taken or expect to take in a tax return .fin 48 is effective for fiscal years beginning after december 15 , 2006 and is required to be adopted by the company beginning in the first quarter of fiscal 2008 .although the company will continue to evaluate the application of fin 48 , management does not currently believe adoption will have a material impact on the company 2019s financial condition or operating results .liquidity and capital resources the following table presents selected financial information and statistics for each of the last three fiscal years ( dollars in millions ) : september 29 , september 30 , september 24 , 2007 2006 2005 .
[['', 'september 29 2007', 'september 30 2006', 'september 24 2005'], ['cash cash equivalents and short-term investments', '$ 15386', '$ 10110', '$ 8261'], ['accounts receivable net', '$ 1637', '$ 1252', '$ 895'], ['inventory', '$ 346', '$ 270', '$ 165'], ['working capital', '$ 12657', '$ 8066', '$ 6813'], ['annual operating cash flow', '$ 5470', '$ 2220', '$ 2535']]
as of september 29 , 2007 , the company had $ 15.4 billion in cash , cash equivalents , and short-term investments , an increase of $ 5.3 billion over the same balance at the end of september 30 , 2006 .the principal components of this net increase were cash generated by operating activities of $ 5.5 billion , proceeds from the issuance of common stock under stock plans of $ 365 million and excess tax benefits from stock-based compensation of $ 377 million .these increases were partially offset by payments for acquisitions of property , plant , and equipment of $ 735 million and payments for acquisitions of intangible assets of $ 251 million .the company 2019s short-term investment portfolio is primarily invested in highly rated , liquid investments .as of september 29 , 2007 and september 30 , 2006 , $ 6.5 billion and $ 4.1 billion , respectively , of the company 2019s cash , cash equivalents , and short-term investments were held by foreign subsidiaries and are generally based in u.s .dollar-denominated holdings .the company believes its existing balances of cash , cash equivalents , and short-term investments will be sufficient to satisfy its working capital needs , capital expenditures , outstanding commitments , and other liquidity requirements associated with its existing operations over the next 12 months. .

Question: what was the change between september 29 , 2007 and september 30 , 2006 , of the company 2019s cash , cash equivalents , and short-term investments were held by foreign subsidiaries and based in u.s . dollar-denominated holdings , in billions?
Answer: 2.4