As of the census of 2000, there were 16,461 people, 6,517 households, and 4,112 families residing in the city. The population density was 1,548.8 people per square mile (597.9/km²). There were 7,536 housing units at an average density of 709.1/sq mi (273.7/km²). The racial makeup of the city was 84.87% White, 0.47% African American, 3.70% Native American, 2.10% Asian, 0.14% Pacific Islander, 5.15% from other races, and 3.57% from two or more races. Hispanic or Latino of any race were 9.22% of the population. 16.4% were of German, 9.3% English, 9.3% American, 8.7% Irish and 5.9% Norwegian ancestry according to Census 2000. 90.2% spoke English and 7.7% Spanish as their first language.
There were 6,517 households out of which 31.8% had children under the age of 18 living with them, 43.9% were married couples living together, 13.7% had a female householder with no husband present, and 36.9% were non-families. 29.5% of all households were made up of individuals and 12.0% had someone living alone who was 65 years of age or older. The average household size was 2.49 and the average family size was 3.05.
In the city the population was spread out with 26.8% under the age of 18, 10.3% from 18 to 24, 27.1% from 25 to 44, 21.9% from 45 to 64, and 14.0% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 98.0 males. For every 100 females age 18 and over, there were 96.0 males.
The median income for a household in the city was $30,683, and the median income for a family was $37,966. Males had a median income of $32,710 versus $20,446 for females. The per capita income for the city was $16,092. About 16.1% of families and 22.2% of the population were below the poverty line, including 29.7% of those under age 18 and 9.6% of those age 65 or over.