More interesting (to me) would be the number of applications actually used after the first day they were installed.
My pattern with mobile apps goes something like this:
I download a lot of apps to see what I like, especially after I get a new device. In the case of Android I buy a lot of apps when they go on sale.
But only regularly use about a dozen apps. That includes stuff like a browser, mail, and instant messaging. I've downloaded a lot of apps. I used to even download apps that were "website replacements" or a website front-end. But then I realized that every day my phone was automatically updating 20 apps a day (on average). And none of these apps were actually in use. In the case of iOS, my OCD was causing me to have to download whatever updates the app store had for me in the little red dot.
Since then I've started uninstalling apps if I haven't used it in a month after the first installation.
Right now I'm going through the "collect all sorts of apps" phase with metro apps on Windows 8.
Ultimately, I wish apps worked more like websites (with the performance of native code). You go to use them, and then you automatically download the bits that you need and those bits get "cached" on local storage. If you don't a app for a while, it gets cleaned out of your cache. And if you go to use the app and there are updates, those get downloaded on demand. I think this is a model that would work better for "normal people". But I guess that is for operating systems of the future to implement.