I wonder what number of distinct users is. Once you go Android, you tend to stay there. Between my wife and me, for example, we have had 6 Android phones (1 HTC Hero, 2 HTC Evo 4Gs, 3 HTC Amaze 4Gs), and 5th Android tablet (2 Samsung Galaxy Tabs, 1 Asus Transformer, 1 Acer Iconia, and 1 T-Mobile G-Slate). I'm sure each activation was recorded, but there isn't really a way to deactivate a device. Even a factory reset appears to be restricted to the phone, and doesn't register anything with the carrier/Google.