Google has introduced a new monthly report to give developers on the Android Market more information about users of their paid applications. The reports will contain information from each purchase, but will not contain any data that could be used to individually identify users. Instead, basics like what device was used and what currency the purchase was made in will be recorded.
The March 2011 report is up for download right now, and Google will be making past months' data going back to January 2011 available in the coming weeks. In the future, Google expects to release the data on a monthly basis with each month's data being released by the 10th day of the following month. [Android Developers Blog]