2000 146,798 1990 128,932 1980 119,816 1970 87,114 1960 60,279 1950 40,076 1940 27,836 1930 22,821 1920 20,256 1910 20,540 1900 19,175 1890 18,052 1880 17,227 1870 13,942 1860 10,313 1850 5,234 1840 2,162
As of the census of 2000, there were 146,798 people, 54,649 households, and 39,729 families residing in the county. The population density was 351 people per square mile (136/km²). There were 57,616 housing units at an average density of 138 per square mile (53/km²). The racial makeup of the county was 95.33% White, 0.92% Black or African American, 0.22% Native American, 0.91% Asian, 0.03% Pacific Islander, 1.26% from other races, and 1.32% from two or more races. 4.82% of the population were Hispanic or Latino of any race. 23.7% were of German, 12.3% Irish, 8.3% Polish, 8.0% English and 7.9% American ancestry according to Census 2000.
There were 54,649 households out of which 35.00% had children under the age of 18 living with them, 59.80% were married couples living together, 9.20% had a female householder with no husband present, and 27.30% were non-families. 22.20% of all households were made up of individuals and 8.00% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.08.
In the county the population was spread out with 25.80% under the age of 18, 9.80% from 18 to 24, 28.90% from 25 to 44, 24.60% from 45 to 64, and 10.90% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 96.40 males. For every 100 females age 18 and over, there were 93.90 males.
The median income for a household in the county was $53,100, and the median income for a family was $61,880. Males had a median income of $50,167 versus $26,347 for females. The per capita income for the county was $23,957. About 3.90% of families and 5.90% of the population were below the poverty line, including 6.80% of those under age 18 and 5.60% of those age 65 or over.