As of the census of 2000, there were 21,310 people, 7,734 households, and 5,189 families residing in the county. The population density was 31 people per square mile (12/km2). There were 8,208 housing units at an average density of 12 per square mile (5/km2). The racial makeup of the county was 97.85% White, 0.51% Black or African American, 0.08% Native American, 0.82% Asian, 0.24% from other races, and 0.50% from two or more races. 0.80% of the population were Hispanic or Latino of any race. 38.3% were of German, 31.7% Norwegian, 5.5% Irish and 5.1% Czech ancestry.