It's important to keep in mind that the requirement is to report and analyze prior sales and transfers. I believe that "transfers" include a large number of transactions that are not necessarily sales (as in quit claims of a property interest), special deeds (as in executor or personal representative deeds), deeds in lieu of foreclosure, etc.
In this area, we can get access to a public records reporting service through our MLS subscription; from MPC (in one county); and, from the Comptroller of the Currency in the state capitol.