For years now, the main growth area for GameStop has been used games, and its financials last week once again confirm that.

Used games have been so profitable for GameStop, that it has been shifting its business for years to emphasize used game sales, decreasing the amount of new product available in stores and pinning its advertising on the ability to buy and sell used games. Other businesses have been launched to follow GameStop’s lead, pursuing used game sales.

Many gamers first began to notice this when Penny Arcade complained about the topic. Penny Arcade even compared GameStop’s business to that of a pawn shop.

Once again, GameStop’s filings with the US Securities and Exchange Commission confirm that its bread and butter are the used games trade. During the latest fiscal quarter ended November 3, 2007, 22.1% of GameStop’s sales came from used game products, while 39.5% came from new game software and 23.2% came from new game hardware. That doesn’t sound like a big deal, but GameStop makes a larger profit on used game sales. As a result, used game products accounted for $48.5% of gross profits, while new game software and hardware together only accounted for 28.1% of gross profits.

Used games have provided GameStop with a comparable percentage of profits in the past, and will continue to do so. They simply make a lot more money selling used games than from selling new games.