500 million apps downloaded

In an ad in the New York Time, Apple announced that 500 million apps have been downloaded from the App Store. Notes Silicon Alley Insider:

It took 61 days for Apple to reach 100 million apps downloaded (1.6 million per day), 43 days to reach 200 million (2.3 million per day), and another 43 days to reach 300 million (2.3 million per day).

And only 400 million of those 500 million downloads are fart-related apps.