american tower corporation and subsidiaries notes to consolidated financial statements 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 ) : .
what was the average bad debt allowance for the past three years , in billions?
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 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 during the year ended december 31 , 2010 . as a result of the renegotiation of the company 2019s agreements with grupo iusacell , s.a . de c.v . ( 201ciusacell 201d ) , which included , among other changes , converting iusacell 2019s contractual obligations to the company from u.s . dollars to mexican pesos , the company 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 equity . the change in functional currency from u.s . dollars to mexican pesos gave rise to a decrease in the net value of certain non-monetary assets and liabilities . the aggregate impact on such assets and liabilities was $ 33.6 million with an offsetting decrease in accumulated other comprehensive income . the functional currency of the company 2019s other foreign operating subsidiaries is also the respective local currency . all assets and liabilities held by the subsidiaries are translated into u.s . dollars at the exchange rate in effect at the end of the applicable fiscal reporting period . revenues and expenses are translated at the average monthly exchange rates . the cumulative translation effect is included in equity as a component of accumulated other comprehensive income . foreign currency transaction gains and losses are recognized in the consolidated statements of operations and are the result of transactions of a subsidiary being denominated in a currency other than its functional currency . cash and cash equivalents 2014cash and cash equivalents include cash on hand , demand deposits and short-term investments , including money market funds , with remaining maturities of three months or less when acquired , whose cost approximates fair value . restricted cash 2014the company classifies as restricted cash all cash pledged as collateral to secure obligations and all cash whose use is otherwise limited by contractual provisions , including cash on deposit in reserve accounts relating to the commercial mortgage pass-through certificates , series 2007-1 issued in the company 2019s securitization transaction and the secured cellular site revenue notes , series 2010-1 class c , series 2010-2 class c and series 2010-2 class f , assumed by the company as a result of the acquisition of certain legal entities from unison holdings , llc and unison site management ii , l.l.c . ( collectively , 201cunison 201d ) . .