NPD Group figures confirm that the franchise as a whole has raked in a cool $1 billion in North America alone.

Since its initial release in 2005, the Guitar Hero franchise has sold in excess of 14 million units in North America alone, according to The NPD Group. In ten weeks since the game's launch, consumers have already downloaded more than five million songs.

“Guitar Hero is one of the biggest brands and one of the most powerful distribution platforms in all of entertainment today,” said president and chief executive officer at Activision Michael Griffith. “Guitar Hero's popularity with broad audiences is a confirmation that video games have become a true mass medium.”