years of age or older. The average household size was 2.62 and the average family size was 3.08. In the city, the population was spread out, with 28.7% under the age of 18, 5.4% from 18 to 24, 27.5% from 25 to 44, 23.1% from 45 to 64, and 15.4% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 105.3 males. For every 100 females age 18 and over, there were 102.6 males. The median income for a household in the city was $32,344, and the median income for a family was $40,179. Males had a median income of $31,042 versus $20,250 for females. The per capita income for the city was $12,888. About 4.1% of families and 6.3% of the population were below the poverty line, including 3.5% of those under age 18 and 6.3% of those age 65 or over. Education Plymouth's public schools are operated by the Central Springs Community School District, established on July 1, 2011, by the merger of North Central Community School District and Nora Springs–Rock Falls Community School District. Prior to the merger, it was in the North Central district. References Cities in Cerro Gordo County, Iowa Cities in Iowa Mason City, Iowa micropolitan area