united parcel service , inc . and subsidiaries notes to consolidated financial statements 2014 ( continued ) the following table summarizes the activity related to our unrecognized tax benefits ( in millions ) : .

$ 373: additions for tax positions of the current year: 13
additions for tax positions of prior years: 34
changes in judgment or facts: -12
settlements during the period: -49
lapses of applicable statute of limitations: -4
balance at december 31 2007: 355

as of december 31 , 2007 , the total amount of gross unrecognized tax benefits that , if recognized , would affect the effective tax rate was $ 134 million . we also had gross recognized tax benefits of $ 567 million recorded as of december 31 , 2007 associated with outstanding refund claims for prior tax years . therefore , we had a net receivable recorded with respect to prior year income tax matters in the accompanying balance sheets . our continuing practice is to recognize interest and penalties associated with income tax matters as a component of income tax expense . related to the uncertain tax benefits noted above , we accrued penalties of $ 5 million and interest of $ 36 million during 2007 . as of december 31 , 2007 , we have recognized a liability for penalties of $ 6 million and interest of $ 75 million . additionally , we have recognized a receivable for interest of $ 116 million for the recognized tax benefits associated with outstanding refund claims . we file income tax returns in the u.s . federal jurisdiction , most u.s . state and local jurisdictions , and many non-u.s . jurisdictions . as of december 31 , 2007 , we had substantially resolved all u.s . federal income tax matters for tax years prior to 1999 . in the third quarter of 2007 , we entered into a joint stipulation to dismiss the case with the department of justice , effectively withdrawing our refund claim related to the 1994 disposition of a subsidiary in france . the write-off of previously recognized tax receivable balances associated with the 1994 french matter resulted in a $ 37 million increase in income tax expense for the quarter . however , this increase was offset by the impact of favorable developments with various other u.s . federal , u.s . state , and non-u.s . contingency matters . in february 2008 , the irs completed its audit of the tax years 1999 through 2002 with only a limited number of issues that will be considered by the irs appeals office by 2009 . the irs is in the final stages of completing its audit of the tax years 2003 through 2004 . we anticipate that the irs will conclude its audit of the 2003 and 2004 tax years by 2009 . with few exceptions , we are no longer subject to u.s . state and local and non-u.s . income tax examinations by tax authorities for tax years prior to 1999 , but certain u.s . state and local matters are subject to ongoing litigation . a number of years may elapse before an uncertain tax position is audited and ultimately settled . it is difficult to predict the ultimate outcome or the timing of resolution for uncertain tax positions . it is reasonably possible that the amount of unrecognized tax benefits could significantly increase or decrease within the next twelve months . items that may cause changes to unrecognized tax benefits include the timing of interest deductions , the deductibility of acquisition costs , the consideration of filing requirements in various states , the allocation of income and expense between tax jurisdictions and the effects of terminating an election to have a foreign subsidiary join in filing a consolidated return . these changes could result from the settlement of ongoing litigation , the completion of ongoing examinations , the expiration of the statute of limitations , or other unforeseen circumstances . at this time , an estimate of the range of the reasonably possible change cannot be .

Questions:
what was the net change in the unrecognized tax benefit between 1/1/07 and 12/31/07?
what percentage of the balance of unrecognized tax benefits as of 12/17 impacts the effective tax rate?

Answers:
-18
37.7%