The activity in the allowance for doubtful accounts consisted of the following:
| Balance at | ||||||||||||||||
| beginning | Provision | Balance at | ||||||||||||||
| Fiscal Year | of year | Additions | Write-offs | end of year | ||||||||||||
| September 30, 2012 | $ | 13,816 | $ | 4,619 | $ | (4,971 | ) | $ | 13,464 | |||||||
| September 30, 2011 | $ | 11,817 | $ | 7,960 | $ | (5,960 | ) | $ | 13,816 | |||||||
| September 30, 2010 | $ | 13,442 | $ | 4,622 | $ | (6,247 | ) | $ | 11,817 | |||||||