human
allowance for doubtful accounts is as follows:.
|  | 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 |
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.
Please answer the following question with expressions if necessary.
what percentage change does this represent?
assistant
subtract(185, 160), divide(#0, 160)