The average household size was 2.27 and the average family size was 2.71. The median age in the city was 40.6 years. 22% of residents were under the age of 18; 9.1% were between the ages of 18 and 24; 26.9% were from 25 to 44; 26.5% were from 45 to 64; and 15.4% were 65 years of age or older. The gender makeup of the city was 49.7% male and 50.3% female. As of the census of 2000, there were 399 people, 139 households, and 92 families residing in the city. The population density was 1,391.4 people per square mile (531.2/km²). There were 169 housing units at an average density of 589.3 per square mile (225.0/km²). The racial makeup of the city was 97.24% White, 0.25% Asian, and 2.51% from two or more races. There were 139 households out of which 32.4% had children under the age of 18 living with them, 57.6% were married couples living together, 3.6% had a female householder with no husband present, and 33.1% were non-families. 28.8% of all households were made up of individuals and 18.0% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.25. In the city, the population was spread out with 27.6% under the age of 18, 7.0% from 18 to 24, 24.3% from 25 to 44, 17.3% from 45 to 64, and 23.8% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 106.7 males. For every 100 females age 18 and over, there were 96.6 males. The median income for a household in the city was $29,167, and the median income for a family was $33,750. Males had a median income of $25,313 versus $16,250 for females. The per capita income for the city was $12,641. About 9.2% of families and 12.0% of the population were below the poverty line, including 17.5% of those under age 18 and 1.9% of those age 65 or over. Jamestown is mostly a small agricultural community.