In 2000, there were 44,771 housing units at an average density of 2,016.7 per square mile (778.7/km2). There were 43,609 households, out of which 33.0% had children under the age of 18 living with them, 51.8% were married couples living together, 11.0% had a female householder with no husband present, and 32.1% were non-families. 23.5% of all households were made up of individuals, and 7.3% had someone living alone who was 65 years of age or older. The average household size was 2.83 and the average family size was 3.37.