2020 census
As of the 2020 census, the county had a population of 20,990. The median age was 45.4 years; 21.3% of residents were under the age of 18 and 23.1% of residents were 65 years of age or older. For every 100 females there were 99.6 males, and for every 100 females age 18 and over there were 97.7 males age 18 and over. [12]
The racial makeup of the county was 96.2% White, 0.3% Black or African American, 0.2% American Indian and Alaska Native, 0.4% Asian, <0.1% Native Hawaiian and Pacific Islander, 0.5% from some other race, and 2.4% from two or more races. Hispanic or Latino residents of any race comprised 1.0% of the population. [13]
23.5% of residents lived in urban areas, while 76.5% lived in rural areas. [14]
There were 8,914 households in the county, of which 26.2% had children under the age of 18 living in them. Of all households, 53.2% were married-couple households, 18.4% were households with a male householder and no spouse or partner present, and 22.1% were households with a female householder and no spouse or partner present. About 28.9% of all households were made up of individuals and 14.6% had someone living alone who was 65 years of age or older. [12]
There were 10,015 housing units, of which 11.0% were vacant. Among occupied housing units, 79.7% were owner-occupied and 20.3% were renter-occupied. The homeowner vacancy rate was 2.0% and the rental vacancy rate was 8.5%. [12]
2010 census
As of the 2010 United States census, there were 22,363 people, 9,216 households, and 6,376 families living in the county. [24] The population density was 29.5 inhabitants per square mile (11.4/km2). There were 10,396 housing units at an average density of 13.7 per square mile (5.3/km2). [5] The racial makeup of the county was 98.6% white, 0.3% Asian, 0.2% American Indian, 0.2% black or African American, 0.2% from other races, and 0.6% from two or more races. Those of Hispanic or Latino origin made up 0.8% of the population. [24] In terms of ancestry, 25.5% were German, 9.9% were English, 9.8% were American, and 8.8% were Irish. [25]
Of the 9,216 households, 29.2% had children under the age of 18 living with them, 57.1% were married couples living together, 8.0% had a female householder with no husband present, 30.8% were non-families, and 27.1% of all households were made up of individuals. The average household size was 2.40 and the average family size was 2.90. The median age was 43.5 years. [24]
The median income for a household in the county was $44,627 and the median income for a family was $55,655. Males had a median income of $40,119 versus $27,860 for females. The per capita income for the county was $21,891. About 7.8% of families and 11.3% of the population were below the poverty line, including 16.7% of those under age 18 and 8.1% of those age 65 or over. [26]
United States
Illinois 
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