interesting, but I would love to know the amount of applications in iOS / Android with installation base >= N (with N something like 100). I doubt such a data is available unfortunately.
However the App store is not making a good job at all trying to help users to discover "long tail" applications that are well designed and useful. It's all about stressing the few tops that everybody already know. I hope the Android market is better in this regard.
I can't give you an exact answer, but I can tell you this... out of the 224,133 apps I track in the android market, here is the breakdown of how many installs they have as of this morning: http://dl.dropbox.com/u/131/installs.csv
I believe AppBrain released some stats not too long ago, the vast majority of Apps do verry poorly if I remember correctly, will try and find the report.
However the App store is not making a good job at all trying to help users to discover "long tail" applications that are well designed and useful. It's all about stressing the few tops that everybody already know. I hope the Android market is better in this regard.