I don't know about the rest of you, but I spent over $100 on iPad apps the day I got it (I knew what I wanted!) and am sure I've spent hundreds over the three years I've had my iPhone.
Everyone I know with iOS devices has at least $25 worth of apps on each, if not many, many more.
Given the number of words like "about" and "roughly" and "estimate" and "gut feeling", I'm going to believe my anecdotal evidence over this.
I'd like to see a similar breakdown, but with more substantial data. Ah, but that would be a pipe dream. Apple is a locked box. And that is okay.