american tower corporation and subsidiaries notes to consolidated financial statements 2014 ( continued ) basis step-up from corporate restructuring represents the tax effects of increasing the basis for tax purposes of certain of the company 2019s assets in conjunction with its spin-off from american radio systems corporation , its former parent company .at december 31 , 2006 , the company had net federal and state operating loss carryforwards available to reduce future taxable income of approximately $ 2.1 billion and $ 2.5 billion , respectively .if not utilized , the company 2019s net operating loss carryforwards expire as follows ( in thousands ) : .
[['years ended december 31,', 'federal', 'state'], ['2007 to 2011', '', '$ 438967'], ['2012 to 2016', '', '478502'], ['2017 to 2021', '$ 617039', '1001789'], ['2022 to 2026', '1476644', '629354'], ['total', '$ 2093683', '$ 2548612']]
sfas no .109 , 201caccounting for income taxes , 201d requires that companies record a valuation allowance when it is 201cmore likely than not that some portion or all of the deferred tax assets will not be realized . 201d at december 31 , 2006 , the company has provided a valuation allowance of approximately $ 308.2 million , including approximately $ 153.6 million attributable to spectrasite , primarily related to net operating loss and capital loss carryforwards assumed as of the acquisition date .the balance of the valuation allowance primarily relates to net state deferred tax assets .the company has not provided a valuation allowance for the remaining deferred tax assets , primarily its federal net operating loss carryforwards , as management believes the company will have sufficient time to realize these federal net operating loss carryforwards during the twenty-year tax carryforward period .valuation allowances may be reversed if related deferred tax assets are deemed realizable based on changes in facts and circumstances relevant to the assets 2019 recoverability .approximately $ 148.3 million of the spectrasite valuation allowances as of december 31 , 2006 will be recorded as a reduction to goodwill if the underlying deferred tax assets are utilized .the company intends to recover a portion of its deferred tax asset through its federal income tax refund claims related to the carry back of certain federal net operating losses .in june 2003 and october 2003 , the company filed federal income tax refund claims with the irs relating to the carry back of $ 380.0 million of net operating losses generated prior to 2003 , of which the company initially anticipated receiving approximately $ 90.0 million .based on preliminary discussions with tax authorities , the company revised its estimate of the net realizable value of the federal income tax refund claims during the year ended december 31 , 2005 , and anticipates receiving a refund of approximately $ 65.0 million , plus interest .the company expects settlement of this matter in the first half of 2007 , however , there can be no assurances with respect to the timing of any refund .because of the uncertainty associated with the claim , the company has not recognized any amounts related to interest .the recoverability of the company 2019s remaining net deferred tax asset has been assessed utilizing stable state ( no growth ) projections based on its current operations .the projections show a significant decrease in depreciation in the later years of the carryforward period as a result of a significant portion of its assets being fully depreciated during the first fifteen years of the carryforward period .accordingly , the recoverability of the net deferred tax asset is not dependent on material improvements to operations , material asset sales or other non-routine transactions .based on its current outlook of future taxable income during the carryforward period , management believes that the net deferred tax asset will be realized .the realization of the company 2019s deferred tax assets as of december 31 , 2006 will be dependent upon its ability to generate approximately $ 1.4 billion in taxable income from january 1 , 2007 to december 31 , 2026 .if the company is unable to generate sufficient taxable income in the future , or carry back losses , as described above , it .

Question: what portion of state operating loss carryforwards expire between 2017 and 2021?
Answer: 39.3%