sentences:  In terms of ancestry, 28.9% were German, 19.3% were English, 14.1% were Irish, and 9.0% were American.Of the 21,149 households, 38.8% had children under the age of 18 living with them, 61.1% were married couples living together, 8.4% had a female householder with no husband present, 26.7% were non-families, and 22.4% of all households were made up of individuals.The average household size was 2.65 and the average family size was 3.12.