sentences:  Of the 20,856 households, 33.1% had children under the age of 18 living with them, 56.1% were married couples living together, 9.7% had a female householder with no husband present, 29.5% were non-families, and 24.5% of all households were made up of individuals.The average household size was 2.54 and the average family size was 3.01.The median age was 40.7 years.