The Call of Duty franchise has now sold over 20 million map packs in total since the series began in 2003.
Chart-Track, GfK and the NPD Group all rate the first-person shooter as the US and Europe's number one selling first-person action game, sales helped in no small part by the superb performance of Call of Duty: Modern Warfare and its sequel at retail.
"The Call of Duty franchise is unique in the world of entertainment and delivers one of the best multiplayer experiences ever. We are thrilled to deliver to fans exciting and engaging content that has the intensity they have come to expect from the franchise," said Activision CEO Bobby Kotick.
Earlier this year, Activision revealed that only 30 per cent of its $318 million yearly profit comes from console game sales, whilst Kotick has suggested that players might be happy to pay for an online Call of Duty experience.