 32.1% were of German, 14.7% Norwegian, 7.2% Irish and 5.3% Czech ancestry.There were 18,888 households out of which 36.50% had children under the age of 18 living with them, 58.10% were married couples living together, 8.60% had a female householder with no husband present, and 29.30% were non-families.23.90% of all households were made up of individuals and 9.10% had someone living alone who was 65 years of age or older.