 32.3% were of German, 11.6% Swedish, 11.1% Norwegian and 5.5% American ancestry.There were 17,276 households out of which 31.20% had children under the age of 18 living with them, 56.50% were married couples living together, 8.70% had a female householder with no husband present, and 30.40% were non-families.25.10% of all households were made up of individuals and 10.90% had someone living alone who was 65 years of age or older.