Racial and ethnic composition 2020 census As of the
2020 census, the county had a population of 406,978. The
population density was . There were 172,177 housing units at an average density of . The median age was 43.6 years. 21.8% of residents were under the age of 18 and 19.6% of residents were 65 years of age or older. For every 100 females there were 96.1 males, and for every 100 females age 18 and over there were 93.9 males age 18 and over. There were 164,537 households in the county, of which 28.7% had children under the age of 18 living in them. Of all households, 57.7% were married-couple households, 14.9% were households with a male householder and no spouse or partner present, and 21.9% were households with a female householder and no spouse or partner present. About 25.9% of all households were made up of individuals and 12.3% had someone living alone who was 65 years of age or older. Of these housing units, 4.4% were vacant. Among occupied housing units, 75.2% were owner-occupied and 24.8% were renter-occupied. The homeowner vacancy rate was 0.7% and the rental vacancy rate was 5.1%.
2010 census At the
2010 census there were 389,891 people, 152,663 households, and 108,810 families living in the county. The population density was . There were 160,864 housing units at an average density of . The
racial makeup of the county was 93.3% White, 1.3% Black or African American, 0.3% Native American, 2.7% Asian, 0.0003% Pacific Islander, 1.0% from
other races, and 1.3% from two or more races. 4.1% of the population were Hispanic or Latino of any race. Of the 152,663 households 30.8% had children under the age of 18 living with them, 60.7% were married couples living together, 7.1% had a female householder with no husband present, and 28.7% were non-families. 23.8% of households were one person and 10.1% were one person aged 65 or older. The average household size was 2.52 and the average family size was 3.00. The age distribution was 24.1% under the age of 18, 6.8% from 18 to 24, 23.6% from 25 to 44, 31.2% from 45 to 64, and 14.3% 65 or older. The median age was 42 years. For every 100 females there were 96.30 males. For every 100 females age 18 and over, there were 93.90 males.
2000 census At the
2000 census there were 360,767 people, 135,229 households, and 100,475 families living in the county. The population density was . There were 140,309 housing units at an average density of . The
racial makeup of the county was 95.77% White, 0.73% Black or African American, 0.22% Native American, 1.49% Asian, 0.02% Pacific Islander, 0.87% from other races, and 0.90% from two or more races. 2.63% of the population were Hispanic or Latino of any race. 44.5% were of
German, 9.2%
Polish, 7.5%
Italian, and 7.7%
Irish ancestry according to
Census 2000. 94.3% spoke
English, 2.2%
Spanish and 1.2%
German as their first language. Of the 135,229 households 35.40% had children under the age of 18 living with them, 64.80% were married couples living together, 6.80% had a female householder with no husband present, and 25.70% were non-families. 20.90% of households were one person and 8.10% were one person aged 65 or older. The average household size was 2.63 and the average family size was 3.08. The age distribution was 26.30% under the age of 18, 6.80% from 18 to 24, 29.80% from 25 to 44, 25.10% from 45 to 64, and 12.00% 65 or older. The median age was 38 years. For every 100 females there were 96.80 males. For every 100 females age 18 and over, there were 94.40 males. The median household income was $62,839 and the median family income was $71,773. Males had a median income of $49,232 versus $31,643 for females. The per capita income for the county was $29,164. About 1.7% of families and 2.7% of the population were below the poverty line, including 2.5% of those under age 18 and 4.0% of those age 65 or over. ==Government==