So, the most pirated title of 2011 was Crysis 2. According to TorrentFreak, (I'm getting this info from an article on this very website) 3,920,000 copies were torrented. I'll assume torrents make up 75% of the total pirated copies, bringing it up to about 5,230,000 copies total. I'm having trouble finding stats about the number of copies sold, but the number that seems to be popping up most often is 3 million (Someone correct me if I'm wrong).
5,230,000 + 3,000,000= 8,230,000. Some quick calculation, and it brings us to the conclusion that of the most pirated game of 2011, about 63% of copies were pirated. But if the MOST PIRATED GAME of 2011 only had 63% (4 out of 10 legally bought, as opposed to, y'know 1 out of 20), somehow I doubt the figures Guillemot was throwing around were very accurate.
Somewhat offtopic: Wow, I certainly didn't expect that figure to be that high. I thought 30% for the most pirated game, definitely not over 50%. That is REALLY worrying.