{"pre_text": ["american tower corporation and subsidiaries notes to consolidated financial statements recognizing customer revenue , the company must assess the collectability of both the amounts billed and the portion recognized on a straight-line basis .", "this assessment takes customer credit risk and business and industry conditions into consideration to ultimately determine the collectability of the amounts billed .", "to the extent the amounts , based on management 2019s estimates , may not be collectible , recognition is deferred until such point as the uncertainty is resolved .", "any amounts which were previously recognized as revenue and subsequently determined to be uncollectible are charged to bad debt expense .", "accounts receivable are reported net of allowances for doubtful accounts related to estimated losses resulting from a customer 2019s inability to make required payments and reserves for amounts invoiced whose collectability is not reasonably assured .", "these allowances are generally estimated based on payment patterns , days past due and collection history , and incorporate changes in economic conditions that may not be reflected in historical trends , such as customers in bankruptcy , liquidation or reorganization .", "receivables are written-off against the allowances when they are determined uncollectible .", "such determination includes analysis and consideration of the particular conditions of the account .", "changes in the allowances were as follows for the years ended december 31 , ( in thousands ) : ."], "post_text": ["the company 2019s largest international customer is iusacell , which is the brand name under which a group of companies controlled by grupo iusacell , s.a .", "de c.v .", "( 201cgrupo iusacell 201d ) operates .", "iusacell represented approximately 4% ( 4 % ) of the company 2019s total revenue for the year ended december 31 , 2010 .", "grupo iusacell has been engaged in a refinancing of a majority of its u.s .", "dollar denominated debt , and in connection with this process , two of the legal entities of the group , including grupo iusacell , voluntarily filed for a pre-packaged concurso mercantil ( a process substantially equivalent to chapter 11 of u.s .", "bankruptcy law ) with the backing of a majority of their financial creditors in december 2010 .", "as of december 31 , 2010 , iusacell notes receivable , net , and related assets ( which include financing lease commitments and a deferred rent asset that are primarily long-term in nature ) were $ 19.7 million and $ 51.2 million , respectively .", "functional currency 2014as a result of changes to the organizational structure of the company 2019s subsidiaries in latin america in 2010 , the company determined that effective january 1 , 2010 , the functional currency of its foreign subsidiary in brazil is the brazilian real .", "from that point forward , all assets and liabilities held by the subsidiary in brazil are translated into u.s .", "dollars at the exchange rate in effect at the end of the applicable reporting period .", "revenues and expenses are translated at the average monthly exchange rates and the cumulative translation effect is included in stockholders 2019 equity .", "the change in functional currency from u.s .", "dollars to brazilian real gave rise to an increase in the net value of certain non-monetary assets and liabilities .", "the aggregate impact on such assets and liabilities was $ 39.8 million with an offsetting increase in accumulated other comprehensive income ( loss ) .", "as a result of the renegotiation of the company 2019s agreements with its largest international customer , iusacell , which included , among other changes , converting all of iusacell 2019s contractual obligations to the company from u.s .", "dollars to mexican pesos , the company has determined that effective april 1 , 2010 , the functional currency of certain of its foreign subsidiaries in mexico is the mexican peso .", "from that point forward , all assets and liabilities held by those subsidiaries in mexico are translated into u.s .", "dollars at the exchange rate in effect at the end of the applicable reporting period .", "revenues and expenses are translated at the average monthly exchange rates and the cumulative translation effect is included in stockholders 2019 equity .", "the change in functional ."], "table": [["", "2010", "2009", "2008"], ["balance as of january 1,", "$ 28520", "$ 11482", "$ 8850"], ["current year increases", "16219", "26771", "12059"], ["recoveries and other", "-22234 ( 22234 )", "-9733 ( 9733 )", "-9427 ( 9427 )"], ["balance as of december 31,", "$ 22505", "$ 28520", "$ 11482"]], "table_ori": [["", "2010", "2009", "2008"], ["Balance as of January 1,", "$28,520", "$11,482", "$8,850"], ["Current year increases", "16,219", "26,771", "12,059"], ["Recoveries and other", "(22,234)", "(9,733)", "(9,427)"], ["Balance as of December 31,", "$22,505", "$28,520", "$11,482"]]}

Question: what is the percentage change in the balance of allowances from 2009 to 2010?
Evidence:
table_1: the balance as of january 1 , of 2010 is $ 28520 ; the balance as of january 1 , of 2009 is $ 11482 ; the balance as of january 1 , of 2008 is $ 8850 ;
table_4: the balance as of december 31 , of 2010 is $ 22505 ; the balance as of december 31 , of 2009 is $ 28520 ; the balance as of december 31 , of 2008 is $ 11482 ;
Program: subtract(22505, 28520), divide(#0, 28520)
Answer:
str_answer: -21.1%
exe_answer: -0.2109