Who old are Call of Duty games

Call of duty 1 was released in 2003
Call of duty: united offensive in 2004
Call of duty 2 in 2005
Call of duty 3 in 2006
Call of duty 4: modern warfare in 2007
Call of duty: world at war in 2008
Call of duty modern warfare 2 in this year
And the upcoming CoD Call of Duty Black Ops: 2010