But what % of the total user-base actually pirate apps? That is the more important figure.
As an aside: I've "educated" a few acquaintances re: pirating apps on their jailbroken devices. They indicated they getting apps for "free" was a benefit of jailbreaking. I responded by telling them that many of the apps they'd jailbroken were not built by large corporations, but actually indie dev houses or even lone developers. When they realised they weren't 'sticking it to The Man' they appeared to boast a little less about this particular benefit.
Whether it actually changed their behaviour is another thing.