Market research company NPD Group has released its list of best-selling PC games for the week of December 7 – 13.

World of Warcraft’s second expansion Wrath of the Lich King is officially the fastest-selling PC game in history, breaking the last record, set by WoW’s first expansion Burning Crusade, by nearly half a million.

Few games have been as exhaustively detailed ahead of their release as second World of Warcraft expansion, Wrath of the Lich King. After Blizzard failed to plug the leaks from early testing, it resigned itself to the inevitable and lifted any and all non-disclosure restrictions from the public beta test. The insatiable hunger for information of 11 million fans was just too great a force to resist, even for a company as powerful and protective as Blizzard.

And like that, someone already hit 80. A mere 27 hours after World of Warcraft: Wrath of the Lich King launches, the game apparently already has its first level 80: a warlock named Nymh that plays on a French server.

The analyst is also "impressed" at the fact that World of Warcraft's subscriber base has grown to 11 million even amid economic anxieties and two recent major releases, Age of Conan and Warhammer Online, neither of which have appeared to slow the game's momentum. Based on its existing subscriber base, says Hickey, "We expect the upcoming release of WoW’s expansion pack... would yield a sell-through of roughly 5 million units in the first month."