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 ) : .

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

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 .

Question: Analyse this data from a financial earnings document. what is the percentage change in the balance of allowances from 2009 to 2010?
Choices:
-0.5239
0.2109
0.3663
-0.2109
-0.2247
Correct choice index: 3