as of september 24 , 2011 , the total amount of gross unrecognized tax benefits was $ 1.4 billion , of which $ 563 million , if recognized , would affect the company 2019s effective tax rate . as of september 25 , 2010 , the total amount of gross unrecognized tax benefits was $ 943 million , of which $ 404 million , if recognized , would affect the company 2019s effective tax rate . the aggregate changes in the balance of gross unrecognized tax benefits , which excludes interest and penalties , for the three years ended september 24 , 2011 , is as follows ( in millions ) : .

Table:
 | 2011 | 2010 | 2009
beginning balance | $ 943 | 971 | $ 506
increases related to tax positions taken during a prior year | 49 | 61 | 341
decreases related to tax positions taken during a prior year | -39 ( 39 ) | -224 ( 224 ) | -24 ( 24 )
increases related to tax positions taken during the current year | 425 | 240 | 151
decreases related to settlements with taxing authorities | 0 | -102 ( 102 ) | 0
decreases related to expiration of statute of limitations | -3 ( 3 ) | -3 ( 3 ) | -3 ( 3 )
ending balance | $ 1375 | $ 943 | $ 971
the company includes interest and penalties related to unrecognized tax benefits within the provision for income taxes .
as of september 24 , 2011 and september 25 , 2010 , the total amount of gross interest and penalties accrued was $ 261 million and $ 247 million , respectively , which is classified as non-current liabilities in the consolidated balance sheets .
in connection with tax matters , the company recognized interest expense in 2011 and 2009 of $ 14 million and $ 64 million , respectively , and in 2010 the company recognized an interest benefit of $ 43 million .
the company is subject to taxation and files income tax returns in the u.s .
federal jurisdiction and in many state and foreign jurisdictions .
for u.s .
federal income tax purposes , all years prior to 2004 are closed .
the internal revenue service ( the 201cirs 201d ) has completed its field audit of the company 2019s federal income tax returns for the years 2004 through 2006 and proposed certain adjustments .
the company has contested certain of these adjustments through the irs appeals office .
the irs is currently examining the years 2007 through 2009 .
in addition , the company is also subject to audits by state , local and foreign tax authorities .
in major states and major foreign jurisdictions , the years subsequent to 1988 and 2001 , respectively , generally remain open and could be subject to examination by the taxing authorities .
management believes that an adequate provision has been made for any adjustments that may result from tax examinations .
however , the outcome of tax audits cannot be predicted with certainty .
if any issues addressed in the company 2019s tax audits are resolved in a manner not consistent with management 2019s expectations , the company could be required to adjust its provision for income tax in the period such resolution occurs .
although timing of the resolution and/or closure of audits is not certain , the company does not believe it is reasonably possible that its unrecognized tax benefits would materially change in the next 12 months .
note 6 2013 shareholders 2019 equity and share-based compensation preferred stock the company has five million shares of authorized preferred stock , none of which is issued or outstanding .
under the terms of the company 2019s restated articles of incorporation , the board of directors is authorized to determine or alter the rights , preferences , privileges and restrictions of the company 2019s authorized but unissued shares of preferred stock .
comprehensive income comprehensive income consists of two components , net income and other comprehensive income .
other comprehensive income refers to revenue , expenses , gains and losses that under gaap are recorded as an element .

Question: how many years does the irs have under examination?
Answer: 3
Calculation: subtract(2009, 2006)