I might be naive about this, but I really don't believe that a large percentage of those 20000 pirates would have paid for the game if there was no cracked version available for free. I think the ugly truth is that most people either cannot afford to or are unwilling to pay for apps, even if they cost less than a cup of coffee.

Hence I suppose that the piracy factor p = (pirated_copies / legit_copies) is bigger than 1 for most apps - and in many cases a whole lot bigger than one, if the perceived value of the app is especially low.