If you look closely today, you'll notice that some per-app Android Market statistics have lower values; not big differences, but noticeable in a few cases. We discovered last week that, starting in early June, certain events had been double-counted: installs, uninstalls, impressions, and so on. The most obvious symptom was (for paid apps) a discrepancy between the number of installs and the number of reported sales through Checkout.
The underlying problem has been corrected and following data repair, the reported statistics should now be accurate. Our apologies for the glitch.