2005 43,766 2000 43,445 1990 40,307 1980 39,887 1970 37,797 1960 34,093 1950 28,026 1940 25,953 1930 26,552 1920 25,982 1910 26,802 1900 26,491 1890 25,454 1880 25,257 1870 21,892 1860 19,569 1850 15,502 1840 12,005 1830 6,295
As of the census of 2000, there were 43,445 people, 16,561 households, and 12,056 families residing in the county. The population density was 105 people per square mile (41/km²). There were 17,633 housing units at an average density of 43 per square mile (16/km²). The racial makeup of the county was 97.26% White, 0.76% Black or African American, 0.19% Native American, 0.59% Asian, 0.02% Pacific Islander, 0.50% from other races, and 0.68% from two or more races. 1.14% of the population were Hispanic or Latino of any race. 31.1% were of German, 28.3% American, 11.9% English and 9.7% Irish ancestry according to Census 2000.
There were 16,561 households out of which 34.70% had children under the age of 18 living with them, 59.20% were married couples living together, 9.30% had a female householder with no husband present, and 27.20% were non-families. 22.70% of all households were made up of individuals and 9.50% had someone living alone who was 65 years of age or older. The average household size was 2.58 and the average family size was 3.02.
In the county the population was spread out with 26.70% under the age of 18, 8.00% from 18 to 24, 30.60% from 25 to 44, 22.60% from 45 to 64, and 12.20% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 98.00 males. For every 100 females age 18 and over, there were 95.80 males.
The median income for a household in the county was $43,649, and the median income for a family was $51,271. Males had a median income of $36,809 versus $25,021 for females. The per capita income for the county was $20,324. About 4.80% of families and 7.60% of the population were below the poverty line, including 9.70% of those under age 18 and 8.50% of those age 65 or over.