There's a strong power law with app revenue on iOS . The new updates in the iOS App Store continues to favor the top producers.

Among iOS games the bottom 80% of apps make around 3% of the revenue. [1]

This blog post has more information from game developers: http://www.streamingcolour.com/blog/2011/09/28/results-ios-g...

Here's a graph of self-reported revenue among iOS Game Devs: http://www.streamingcolour.com/blog/wp-content/uploads/2011/...

[1] : http://www.streamingcolour.com/blog/wp-content/uploads/2011/...