CoD 4 versus CoD WaW Usage

World At War Sees Less Play Than CoD4? According to GamerDNA analyst Sanya Weathers, who is a former Director of Community for Mythic Entertainment, 64.7 percent of its sampled members have played CoD4 since its November 2007 launch.
“At least ten million copies of the game have sold, but that figure represents sales across all platforms (Gears was initially available only on the Xbox 360, as Gears 2 is at the present time),” Weathers notes. “It too offers a multiplayer component.”
Sales figures for Call of Duty: World at War are harder to pin down, although recent compiled NPD data noted that it sold 4.63 million copies across all formats in the U.S. in 2008. 23 percent of GamerDNA members played World at War title 49 days after its release. But Call Of Duty 4, at the same point in its cycle, had garnered 42 percent of the population.
The following chart shows Call Of Duty player history:
There is MUCH more data at the source link below. Check it out if interested.
Source: GamaSutra