2000 71,435 1990 63,657 1980 65,088 1970 57,022 1960 48,198 1950 36,108 1940 28,276 1930 24,864 1920 23,887 1910 24,813 1900 24,594 1890 23,867 1880 22,777 1870 21,133 1860 17,865 1850 12,428 1840 10,042 1830 5,476
As of the census of 2000, there were 71,435 people, 27,936 households, and 20,058 families residing in the county. The population density was 176 people per square mile (68/km²). There were 29,853 housing units at an average density of 73 per square mile (28/km²). The racial makeup of the county was 94.17% White, 1.83% Black or African American, 0.15% Native American, 1.9% Asian, 0.04% Pacific Islander, 0.96% from other races, and 0.95% from two or more races. 2.24% of the population were Hispanic or Latino of any race. 25.4% were of German, 25.2% American, 11.7% English and 9.1% Irish ancestry according to Census 2000.
There were 27,936 households out of which 33.9% had children under the age of 18 living with them, 58.6% were married couples living together, 9.7% had a female householder with no husband present, and 28.2% were non-families. 24.0% of all households were made up of individuals and 8.8% had someone living alone who was 65 years of age or older. The average household size was 2.52 and the average family size was 2.98.
In the county the population was spread out with 26.5% under the age of 18, 7.7% from 18 to 24, 29.70% from 25 to 44, 24.0% from 45 to 64, and 12.1% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 96.6 males. For every 100 females age 18 and over, there were 93.9 males.
The median income for a household in the county was $44,184, and the median income for a family was $52,097. Males had a median income of $38,350 versus $24,652 for females. The per capita income for the county was $21,536. About 5.9% of families and 7.3% of the population were below the poverty line, including 9.20% of those under age 18 and 7.9% of those age 65 or over.