Figures above reflect correction of the data in Sioux County. Official Canvass swapped figures for Harkin and Tauke in Sioux County. Totals from the canvass are: Harkin: 535,975, Tauke: 446,869.
Source for Popular Vote data: Iowa Secretary of State, comp., "United States Senator," 1990 General Election November 6, 1990 Official Canvass Summary (Des Moines, 1990)