obviously there are people who downloaded it multiple times

Its been around and on enough different platforms that most people who use it would have lost count of how many times they have downloaded it.

I currently have it installed on 4 android devices (my phone, my tablet, my sons tablet, google TV dongle), 3 windows devices (personal PC, loungeroom PC, work PC), and 1 Xbox. That's 8 installs in current use but if you factor in a history of device replacement and software updates I would easily account for hundreds of downloads.