sentences:  In terms of ancestry, 10.8% were German, 8.8% were Irish, 8.5% were English, and 7.0% were American.Of the 20,411 households, 35.7% had children under the age of 18 living with them, 50.3% were married couples living together, 13.0% had a female householder with no husband present, 30.0% were non-families, and 25.5% of all households were made up of individuals.The average household size was 2.59 and the average family size was 3.08.