That figure indicates potentially staggering growth in PC piracy during 2009. Last year Spore, a game that had been much maligned for its security features, claimed the top at only 1.7 million downloads. Besides Modern Warfare 2 more than doubling up on that figure, all five of the most downloaded games of 2009 (the other four being the Sims 3, Prototype, Need for Speed Shift, and Street Figher 4) eclipsed that mark. Video games do show significantly less traffic than the movie industry, though. Star Trek clocked in as the most pirated film of 2009 at almost 11 million downloads, barely edging out Transformers: Revenge of the Fallen at 10.6 million.

The full figures from Torrent Freak follow:

PC Games Downloaded on BitTorrent in 2009

1. Call of Duty: Modern Warfare 2 -- 4,100,000
2. The Sims 3 -- 3,200,000
3. Prototype -- 2,350,000
4. Need for Speed Shift -- 2,100,000
5. Street Fighter 4 -- 1,850,000

Xbox 360 Games Downloaded on BitTorrent in 2009

1. Call of Duty: Modern Warfare 2 -- 970,000
2. Street Figther 4 -- 840,000
3. Prototype -- 810,000
4. Dirt 2 -- 790,000
5. UFC 2009 Undisputed -- 720,000

Wii Games Downloaded on BitTorrent in 2009

1. New Super Mario Bros. -- 1,150,000
2. Punch-Out! -- 950,000
3. Wii Sports Resort -- 920,000
4. The House of the Dead: Overkill -- 860,000
5. Mario Power Tennis -- 830,000