allowance for doubtful accounts is as follows: .
discontinued operations during the fourth quarter of 2009 , schlumberger recorded a net $ 22 million charge related to the resolution of a customs assessment pertaining to its former offshore contract drilling business , as well as the resolution of certain contingencies associated with other previously disposed of businesses . this amount is included in income ( loss ) from discontinued operations in the consolidated statement of income . during the first quarter of 2008 , schlumberger recorded a gain of $ 38 million related to the resolution of a contingency associated with a previously disposed of business . this gain is included in income ( loss ) from discon- tinued operations in the consolidated statement of income . part ii , item 8 .
2010 2009 2008
Balance at beginning of year $160 $133 $86
Provision 38 54 65
Amounts written off (13) (27) (18)
Balance at end of year $185 $160 $133
2010 2009 2008
balance at beginning of year $ 160 $ 133 $ 86
provision 38 54 65
amounts written off -13 ( 13 ) -27 ( 27 ) -18 ( 18 )
balance at end of year $ 185 $ 160 $ 133
what was the percentage increase in the allowance in doubtful accounts from 2009 to 2010