accounts receivable , net october 31 , 2006 october 31 , 2005 dollar change change .
what was the change in dso between 2005 and 2006?
the increase in accounts receivable was primarily due to the increased billings during the fiscal year ended october 31 , 2006 . days sales outstanding ( dso ) was 39 days at october 31 , 2006 and 36 days at october 31 , 2005 . our accounts receivable and dso are primarily driven by our billing and collections activities . net working capital working capital is comprised of current assets less current liabilities , as shown on our balance sheet . as of october 31 , 2006 , our working capital was $ 23.4 million , compared to $ 130.6 million as of october 31 , 2005 . the decrease in net working capital of $ 107.2 million was primarily due to ( 1 ) a decrease of $ 73.7 million in cash and cash equivalents ; ( 2 ) a decrease of current deferred tax assets of $ 83.2 million , primarily due to a tax accounting method change ; ( 3 ) a decrease in income taxes receivable of $ 5.8 million ; ( 4 ) an increase in income taxes payable of $ 21.5 million ; ( 5 ) an increase in deferred revenue of $ 29.9 million ; and ( 6 ) a net increase of $ 2.8 million in accounts payable and other liabilities which included a reclassification of debt of $ 7.5 million from long term to short term debt . this decrease was partially offset by ( 1 ) an increase in short-term investments of $ 59.9 million ; ( 2 ) an increase in prepaid and other assets of $ 27.4 million , which includes land of $ 23.4 million reclassified from property plant and equipment to asset held for sale within prepaid expense and other assets on our consolidated balance sheet ; and ( 3 ) an increase in accounts receivable of $ 22.4 million . other commitments 2014revolving credit facility on october 20 , 2006 , we entered into a five-year , $ 300.0 million senior unsecured revolving credit facility providing for loans to synopsys and certain of its foreign subsidiaries . the facility replaces our previous $ 250.0 million senior unsecured credit facility , which was terminated effective october 20 , 2006 . the amount of the facility may be increased by up to an additional $ 150.0 million through the fourth year of the facility . the facility contains financial covenants requiring us to maintain a minimum leverage ratio and specified levels of cash , as well as other non-financial covenants . the facility terminates on october 20 , 2011 . borrowings under the facility bear interest at the greater of the administrative agent 2019s prime rate or the federal funds rate plus 0.50% ( 0.50 % ) ; however , we have the option to pay interest based on the outstanding amount at eurodollar rates plus a spread between 0.50% ( 0.50 % ) and 0.70% ( 0.70 % ) based on a pricing grid tied to a financial covenant . in addition , commitment fees are payable on the facility at rates between 0.125% ( 0.125 % ) and 0.175% ( 0.175 % ) per year based on a pricing grid tied to a financial covenant . as of october 31 , 2006 we had no outstanding borrowings under this credit facility and were in compliance with all the covenants . we believe that our current cash , cash equivalents , short-term investments , cash generated from operations , and available credit under our credit facility will satisfy our business requirements for at least the next twelve months. .