what was the percent of the decline in the gross unrecognized tax benefits from 2009 to 2010
approximately $ 32 million of federal tax payments were deferred and paid in 2009 as a result of the allied acquisition . the following table summarizes the activity in our gross unrecognized tax benefits for the years ended december 31: .

|  | 2010 | 2009 | 2008 |
| :--- | :--- | :--- | :--- |
| Balance at beginning of year | $242.2 | $611.9 | $23.2 |
| Additions due to the Allied acquisition | - | 13.3 | 582.9 |
| Additions based on tax positions related to current year | 2.8 | 3.9 | 10.6 |
| Reductions for tax positions related to the current year | - | - | (5.1) |
| Additions for tax positions of prior years | 7.5 | 5.6 | 2.0 |
| Reductions for tax positions of prior years | (7.4) | (24.1) | (1.3) |
| Reductions for tax positions resulting from lapse of statute of limitations | (10.4) | (0.5) | (0.4) |
| Settlements | (11.9) | (367.9) | - |
| Balance at end of year | $222.8 | $242.2 | $611.9 |

new accounting guidance for business combinations became effective for our 2009 financial statements . this new guidance changed the treatment of acquired uncertain tax liabilities . under previous guidance , changes in acquired uncertain tax liabilities were recognized through goodwill . under the new guidance , subsequent changes in acquired unrecognized tax liabilities are recognized through the income tax provision . as of december 31 , 2010 , $ 206.5 million of the $ 222.8 million of unrecognized tax benefits related to tax positions taken by allied prior to the 2008 acquisition . included in the balance at december 31 , 2010 and 2009 are approximately $ 209.1 million and $ 217.6 million of unrecognized tax benefits ( net of the federal benefit on state issues ) that , if recognized , would affect the effective income tax rate in future periods . during 2010 , the irs concluded its examination of our 2005 and 2007 tax years . the conclusion of this examination reduced our gross unrecognized tax benefits by approximately $ 1.9 million . we also resolved various state matters during 2010 that , in the aggregate , reduced our gross unrecognized tax benefits by approximately $ 10.0 million . during 2009 , we settled our outstanding tax dispute related to allied 2019s risk management companies ( see 2013 risk management companies ) with both the department of justice ( doj ) and the internal revenue service ( irs ) . this settlement reduced our gross unrecognized tax benefits by approximately $ 299.6 million . during 2009 , we also settled with the irs , through an accounting method change , our outstanding tax dispute related to intercompany insurance premiums paid to allied 2019s captive insurance company . this settlement reduced our gross unrecognized tax benefits by approximately $ 62.6 million . in addition to these federal matters , we also resolved various state matters that , in the aggregate , reduced our gross unrecognized tax benefits during 2009 by approximately $ 5.8 million . we recognize interest and penalties as incurred within the provision for income taxes in our consolidated statements of income . related to the unrecognized tax benefits previously noted , we accrued interest of $ 19.2 million during 2010 and , in total as of december 31 , 2010 , have recognized a liability for penalties of $ 1.2 million and interest of $ 99.9 million . during 2009 , we accrued interest of $ 24.5 million and , in total at december 31 , 2009 , had recognized a liability for penalties of $ 1.5 million and interest of $ 92.3 million . during 2008 , we accrued penalties of $ 0.2 million and interest of $ 5.2 million and , in total at december 31 , 2008 , had recognized a liability for penalties of $ 88.1 million and interest of $ 180.0 million . republic services , inc . notes to consolidated financial statements , continued .

unrecognized_tax_benefits = 222.8
tax_benefit_2008 = 242.2
decrease = unrecognized_tax_benefits - tax_benefit_2008
percent_decrease = decrease / tax_benefit_2008
answer = percent_decrease * 100