determined that it will primarily be subject to the ietu in future periods , and as such it has recorded tax expense of approximately $ 20 million in 2007 for the deferred tax effects of the new ietu system . as of december 31 , 2007 , the company had us federal net operating loss carryforwards of approximately $ 206 million which will begin to expire in 2023 . of this amount , $ 47 million relates to the pre-acquisition period and is subject to limitation . the remaining $ 159 million is subject to limitation as a result of the change in stock ownership in may 2006 . this limitation is not expected to have a material impact on utilization of the net operating loss carryforwards . the company also had foreign net operating loss carryforwards as of december 31 , 2007 of approximately $ 564 million for canada , germany , mexico and other foreign jurisdictions with various expiration dates . net operating losses in canada have various carryforward periods and began expiring in 2007 . net operating losses in germany have no expiration date . net operating losses in mexico have a ten year carryforward period and begin to expire in 2009 . however , these losses are not available for use under the new ietu tax regulations in mexico . as the ietu is the primary system upon which the company will be subject to tax in future periods , no deferred tax asset has been reflected in the balance sheet as of december 31 , 2007 for these income tax loss carryforwards . the company adopted the provisions of fin 48 effective january 1 , 2007 . fin 48 clarifies the accounting for income taxes by prescribing a minimum recognition threshold a tax benefit is required to meet before being recognized in the financial statements . fin 48 also provides guidance on derecognition , measurement , classification , interest and penalties , accounting in interim periods , disclosure and transition . as a result of the implementation of fin 48 , the company increased retained earnings by $ 14 million and decreased goodwill by $ 2 million . in addition , certain tax liabilities for unrecognized tax benefits , as well as related potential penalties and interest , were reclassified from current liabilities to long-term liabilities . liabilities for unrecognized tax benefits as of december 31 , 2007 relate to various us and foreign jurisdictions . a reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows : year ended december 31 , 2007 ( in $ millions ) .

year ended december 31 2007 ( in $ millions ): balance as of january 1 2007: 193
increases in tax positions for the current year: 2
increases in tax positions for prior years: 28
decreases in tax positions of prior years: -21
settlements: -2
balance as of december 31 2007: 200

included in the unrecognized tax benefits of $ 200 million as of december 31 , 2007 is $ 56 million of tax benefits that , if recognized , would reduce the company 2019s effective tax rate . the company recognizes interest and penalties related to unrecognized tax benefits in the provision for income taxes . as of december 31 , 2007 , the company has recorded a liability of approximately $ 36 million for interest and penalties . this amount includes an increase of approximately $ 13 million for the year ended december 31 , 2007 . the company operates in the united states ( including multiple state jurisdictions ) , germany and approximately 40 other foreign jurisdictions including canada , china , france , mexico and singapore . examinations are ongoing in a number of those jurisdictions including , most significantly , in germany for the years 2001 to 2004 . during the quarter ended march 31 , 2007 , the company received final assessments in germany for the prior examination period , 1997 to 2000 . the effective settlement of those examinations resulted in a reduction to goodwill of approximately $ 42 million with a net expected cash outlay of $ 29 million . the company 2019s celanese corporation and subsidiaries notes to consolidated financial statements 2014 ( continued ) %%transmsg*** transmitting job : y48011 pcn : 122000000 ***%%pcmsg|f-49 |00023|yes|no|02/26/2008 22:07|0|0|page is valid , no graphics -- color : d| .

Questions:
what was the balance of unrecognized tax benefits at the end of 2007?
what was the balance at the start of 2007?
what was the net change?
what was the percent change during the year?

Answers:
200
193
7
3.6%