States which have gotten more urban each decade from 1900 - 2000:
Florida Minnesota South Carolina
Georgia Nebraska South Dakota
Hawaii New Mexico Tennessee
Iowa North Carolina Utah
Kansas North Dakota Virginia
Almost all are either Plains or South Atlantic. Anyone have a reason?
The only decade where IL dropped in urban percent was from 1930 to 1940, and that was by a fraction of a percent. That was a common decade for Midwestern states to see a slight decline, though others also saw a dip from 1970 to 1980.