sentences:  In terms of ancestry, 28.5% were German, 13.1% were American, 12.2% were Irish, and 9.0% were English.Of the 17,302 households, 33.8% had children under the age of 18 living with them, 54.4% were married couples living together, 10.5% had a female householder with no husband present, 29.4% were non-families, and 24.5% of all households were made up of individuals.The average household size was 2.53 and the average family size was 2.98.