I've had an intimate relationship with those numbers for the past decade. Let me just say that on the estimate of the revenues themselves, what we're experiencing is a growth in understanding that comes with experience. When we first embarked on the estimation process with accrual accounting for tax revenues about six years ago, we actually placed a high value on being able to tie the estimates to actual transactions. Effectively, what we tried to do was look at experience subsequent to the year-end to get a good fix on what the reality had been as of the financial statement date. That was a deliberate choice, and I think, frankly, it was a choice that was welcomed by the Office of the Auditor General at the time.
But as we began to understand our methodology and understand some of its systematic biases, we've corrected those over time. We're always willing to make the corrections. However, we make the corrections once we're in a position where we're confident that any change we make will be a change for the better. That process will continue, so I expect we will continue to improve.
With respect to the accounts receivable, the allowance for doubtful account methodology, it took a strong act of will last year to change the methodology from what was happening in the past to what we're going to be doing going forward. We certainly believed at the time that the change was fundamental and very valuable. I think it's obviously early days to declare it a success, but I think so far it's holding up. Frankly, we will follow the same process that I just described, which is to continue to monitor. We will not hesitate in making changes that are required to improve it, if it becomes evident that it's necessary.