Data source: The Disaster Center (1950-1997), Daniel McCarthy of NWS SPC paper (1997-1998) and NOAA's Storm Prediction Center (2000-2020).
Note: As Danniel McCarthy writes, the increase in the number of tornadoes in 1950-2000 can be attributed to better knowledge of tornadoes and tornado formation and a high interest in tornado observation.
Last modified 2020/10/14.