 18.0% were of German, 10.9% English, 10.9% Irish, 10.0% American and 6.3% Norwegian ancestry according to Census 2000.There were 6,439 households out of which 37.7% had children under the age of 18 living with them, 57.9% were married couples living together, 10.4% had a female householder with no husband present, and 27.9% were non-families.22.3% of all households were made up of individuals and 6.7% had someone living alone who was 65 years of age or older.