Call of Duty peak player count statistics that I have tracked for years.
This data can be used to look at the health of the PC Call of Duty community in different ways.

Call of Duty:WWII

Call of Duty:Infinite Warfare / Modern Warfare Remastered

Call of Duty:Black Ops 3

Call of Duty:Advanced Warfare

Call of Duty:Ghosts

Call of Duty:Black Ops 2

Call of Duty:Modern Warfare 3

Call of Duty:Black Ops

Call of Duty:World At War