sentences:  In terms of ancestry, 25.5% were German, 16.8% were Irish, 12.9% were American, and 11.2% were English.Of the 13,487 households, 31.8% had children under the age of 18 living with them, 54.3% were married couples living together, 9.4% had a female householder with no husband present, 31.2% were non-families, and 27.0% of all households were made up of individuals.The average household size was 2.44 and the average family size was 2.92.