this, so went and looked at our stats...
We released the first version of our iPhone "strip poker" app, Poker vs Girls in June of 2009 (really based on the App Store limitations, it would have been better described as bikini poker, but strip poker sounded better! Improved marketing for our poker games was the whole idea.) After a lot of tries, the 2.0 version was accepted in early December 2009.
Version 1.0 had an little banner ad spot at the top, so we could promote our other apps. Version 2.0 needed more space, so we removed the ad. No legitimate purchasers have gotten that version 1.0 since December 2009. In fact the entire app was removed from the App Store in February 2010 as part of Apple's big sexy-app-purge. Nobody has gotten it legally since then.
That's now over 3 1/2 years ago...here's the Google analytics for that 1.0 ad page, which nobody who did purchase the app would have seen in that whole time.
1.6 Million unique page views. Every single one of them would be from a pirated version of the app. (We of course show ads for our other apps on the page that's being shown.) I'd hope some percent of those people do like the game and keep playing it, so one person could be several of those views, coming from different devices, etc. But still.
To compare, it did pretty well before it got removed--the total number of copies sold the entire time it was in the App Store was 22,935.