Nerd Rage: 93-95% of PC games are pirated

I'm going to start out by linking my source for this article. Yves Guillemot is the CEO of Ubisoft and in a recent interview talking about Ubisoft's increased amount of free-to-play games, he throws out that statistic: 93-95% of all PC games are pirated. Without a source or anything, just states it as a fact.  If they're pirated, it wouldn't be as if that number is being reported by their servers or by those pirating the software to begin with. I'd love to know how he came up with the number. I think that he probably looked at an expected sales for one of Ubisoft's games on the PC, like say, Assassin's Creed Revelations, and say that they only made 5-7% of what they expected. "Huh, where did those sales go? They must be pirating!" he says to himself. "I guess we better make our DRM even tougher to crack.