After NPD Group reported video game sales fell in September versus the previous year, Microsoft released some information on its recent sales stories and boasted its success in music-related games.

Xbox LIVE, the company said, has sold over 80% of the downloadable songs for music games and currently averages 3.8 million music downloads per month. Overall, Xbox 360 users have purchased more than 45 million music downloads for games in the "Rock Band" and "Guitar Hero" franchises. Between the two franchises, Xbox accounts for over six million copies of the games.

If Microsoft has an 80% market share for these song downloads, the entire market is doing 4.75 million songs per month.

Harmonix sold six million songs downloads for "Guitar Hero" in the first three months downloadable content was available.

In the two and a half months after the release of "Rock Band," reported Billboard in January, users had purchased 2.5 million songs through the game. "Guitar Hero" users had bought over five million songs in about the same time period.