 By February 2008, the game had sold 4.4 million copies, according to the NPD Group, and by October of the same year the game managed to sell over 7.2 million copies.The game sold 1.46 million copies in December 2008, making it the highest-selling game of the month.Across all of 2008, the game managed to sell 5.28 million copies, making it the best-selling game of 2008.