2000 45,128 1990 42,182 1980 39,155 1970 34,986 1960 32,443 1950 29,468 1940 25,935 1930 25,077 1920 23,744 1910 24,175 1900 25,119 1890 23,818 1880 23,414 1870 20,211 1860 12,722 1850 5,348 1840 1,651
As of the census of 2000, there were 45,128 people, 16,519 households, and 12,191 families residing in the county. The population density was 102 people per square mile (39/km²). There were 18,099 housing units at an average density of 41 per square mile (16/km²). The racial makeup of the county was 95.53% White, 0.30% Black or African American, 0.30% Native American, 0.31% Asian, 0.02% Pacific Islander, 2.54% from other races, and 1.01% from two or more races. 5.90% of the population were Hispanic or Latino of any race. 36.6% were of German, 14.2% American, 8.2% English and 8.0% Irish ancestry according to Census 2000.
There were 16,519 households out of which 35.80% had children under the age of 18 living with them, 61.30% were married couples living together, 8.30% had a female householder with no husband present, and 26.20% were non-families. 22.30% of all households were made up of individuals and 10.00% had someone living alone who was 65 years of age or older. The average household size was 2.69 and the average family size was 3.15.
In the county the population was spread out with 28.10% under the age of 18, 8.70% from 18 to 24, 28.00% from 25 to 44, 22.00% from 45 to 64, and 13.30% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 98.70 males. For every 100 females age 18 and over, there were 94.90 males.
The median income for a household in the county was $42,581, and the median income for a family was $48,527. Males had a median income of $33,999 versus $22,482 for females. The per capita income for the county was $18,427. About 4.80% of families and 6.80% of the population were below the poverty line, including 7.30% of those under age 18 and 6.60% of those age 65 or over.