Let's break this down. Assassin's Creed II sold 9 million copies. Say 10% of those were on PC, or 900,000. And at worst this makes up 5% of all people playing the game on the platform. Which would mean 18 million PC copies out in the wild, 17.1 million of them pirated.
Assassin's creed II Cost $24 million to make. 8.1 million copies at $55 per game (store gets their cut, it's around $5 a copy), $445 million. Plus $45 per PC copy sold (PC games are usually $10 cheaper), so $40 million. Less production costs of $24 million. $461 million net profit. BUT, $45 times 17.1 million pirated copies is $769.5 million in lost sales. So Ubisoft should in theory have made $1.23 billion in profit off this game. Ubisoft's revenue for 2010 (the year ACII was released) was $1.22 billion. So Ubisoft should have made more in profit from ACII than it did in revenue for that entire year. Lost sales were 166% of the profit the game could theoretically make.
I'm pulling a lot of numbers out my butt here since Ubisoft doesn't publish PC sales figures or revenue made from ACII. Though a CBC article suggested it made $310 million off 4.7 million copies worldwide sold at launch. Though that would mean they're making $65 per game, which is implausible. I'm also being generous with PC sales. Even if it was 90,000 copies, that's 1.8 million, or $81 million in lost sales. Still substantial. Still 1/6 of potential revenue lost.
With numbers that high, it begs the question. If piracy is making PC gaming so unprofitable for Ubisoft, why do they continue to produce products for the platform. Businesses don't exist to prop up unprofitable ventures. So if they weren't making money off PC gaming, they wouldn't be in that business. I call shenanigans on their numbers. I think it's probably closer to 5%, not 95%.