sentences:  In terms of ancestry, 11.2% were German, 11.0% were American, 8.0% were Irish, and 6.7% were English.Of the 18,015 households, 37.8% had children under the age of 18 living with them, 49.0% were married couples living together, 14.2% had a female householder with no husband present, 31.5% were non-families, and 26.4% of all households were made up of individuals.The average household size was 2.63 and the average family size was 3.18.