The name Jackson ranked 59th in popularity for males of all ages in a sample of 2000-2003 Social Security Administration statistics and 615th in popularity for males of all ages in a sample of the 1990 US Census.
Though this name appears on the 1990 U.S. Census lists, it is used by only a small percentage of the general population.
In the Middle Ages, a little boy named John might be called Johnny or John-kin. The second of these two nicknames generated the independent names Jankin, Jenkin, Jackin and Jack.
Not all these names have shown the endurance of the ever-likable Jack, but they are remembered in numerous surnames. Witness the many Jennings, Jacksons, Jenkinses and Jenkinsons that populate American telephone directories, and that are coming into vogue as distinguished (if rare) personal names.