pre_text: provision for income taxes increased $ 1791 million in 2012 from 2011 primarily due to the increase in pretax income from continuing operations , including the impact of the resumption of sales in libya in the first quarter of 2012 . the following is an analysis of the effective income tax rates for 2012 and 2011: .
post_text: the effective income tax rate is influenced by a variety of factors including the geographic sources of income and the relative magnitude of these sources of income . the provision for income taxes is allocated on a discrete , stand-alone basis to pretax segment income and to individual items not allocated to segments . the difference between the total provision and the sum of the amounts allocated to segments appears in the "corporate and other unallocated items" shown in the reconciliation of segment income to net income below . effects of foreign operations 2013 the effects of foreign operations on our effective tax rate increased in 2012 as compared to 2011 , primarily due to the resumption of sales in libya in the first quarter of 2012 , where the statutory rate is in excess of 90 percent . change in permanent reinvestment assertion 2013 in the second quarter of 2011 , we recorded $ 716 million of deferred u.s . tax on undistributed earnings of $ 2046 million that we previously intended to permanently reinvest in foreign operations . offsetting this tax expense were associated foreign tax credits of $ 488 million . in addition , we reduced our valuation allowance related to foreign tax credits by $ 228 million due to recognizing deferred u.s . tax on previously undistributed earnings . adjustments to valuation allowances 2013 in 2012 and 2011 , we increased the valuation allowance against foreign tax credits because it is more likely than not that we will be unable to realize all u.s . benefits on foreign taxes accrued in those years . see item 8 . financial statements and supplementary data - note 10 to the consolidated financial statements for further information about income taxes . discontinued operations is presented net of tax , and reflects our downstream business that was spun off june 30 , 2011 and our angola business which we agreed to sell in 2013 . see item 8 . financial statements and supplementary data 2013 notes 3 and 6 to the consolidated financial statements for additional information. .
table: 2012 2011
table: Statutory rate applied to income from continuing operations before income taxes 35% 35%
table: Effects of foreign operations, including foreign tax credits 18 6
table: Change in permanent reinvestment assertion — 5
table: Adjustments to valuation allowances 21 14
table: Tax law changes — 1
table: Effective income tax rate on continuing operations 74% 61%
question: Analyse this data from a financial earnings document. by what percentage did adjustments to valuation allowances increase from 2011 to 2012>