Using 2010 data, there were 28,264 households out of which 31.2% had children under the age of 18 living with them, 28.0% were Marriage living together, 24.7% had a female householder with no husband present, and 45.5% were non-families. 38.6% of all households were made up of individuals and 10.8% had someone living alone who was 65 years of age or older. The average household size was 2.23 and the average family size was 2.98.. which household was least common?