There were 16,620 households out of which 30.90 % had children under the age of 18 living with them , 51.50 % were married couples living together , 14.40 % had a female householder with no husband present , and 30.20 % were not related . There were 16,620 households out of which 30.90 % had children under the age of 18 living with them , 51.50 % were married couples living together , 14.40 % had a female householder with no husband present , and 30.20 % were non-families .