2020 census
As of the 2020 census, the county had a population of 16,179. The median age was 42.8 years. 23.3% of residents were under the age of 18 and 21.9% of residents were 65 years of age or older. For every 100 females there were 97.3 males, and for every 100 females age 18 and over there were 96.4 males age 18 and over. [13]
The racial makeup of the county was 95.5% White, 0.6% Black or African American, 0.2% American Indian and Alaska Native, 0.3% Asian, <0.1% Native Hawaiian and Pacific Islander, 0.6% from some other race, and 2.8% from two or more races. Hispanic or Latino residents of any race comprised 1.1% of the population. [14]
29.5% of residents lived in urban areas, while 70.5% lived in rural areas. [15]
There were 6,774 households in the county, of which 28.1% had children under the age of 18 living in them. Of all households, 51.4% were married-couple households, 18.3% were households with a male householder and no spouse or partner present, and 24.7% were households with a female householder and no spouse or partner present. About 30.0% of all households were made up of individuals and 16.2% had someone living alone who was 65 years of age or older. [13]
There were 7,679 housing units, of which 11.8% were vacant. Among occupied housing units, 78.9% were owner-occupied and 21.1% were renter-occupied. The homeowner vacancy rate was 2.2% and the rental vacancy rate was 11.3%. [13]
2010 census
As of the 2010 United States census, there were 16,760 people, 7,102 households, and 4,853 families living in the county. [25] The population density was 23.5 inhabitants per square mile (9.1/km2). There were 7,975 housing units at an average density of 11.2 per square mile (4.3/km2). [4] The racial makeup of the county was 98.0% white, 0.4% Asian, 0.3% black or African American, 0.2% American Indian, 0.3% from other races, and 0.8% from two or more races. Those of Hispanic or Latino origin made up 1.1% of the population. [25] In terms of ancestry, 17.0% were German, 14.1% were English, 12.7% were American, and 9.8% were Irish. [26]
Of the 7,102 households, 28.7% had children under the age of 18 living with them, 55.1% were married couples living together, 9.1% had a female householder with no husband present, 31.7% were non-families, and 28.4% of all households were made up of individuals. The average household size was 2.35 and the average family size was 2.86. The median age was 42.9 years. [25]
The median income for a household in the county was $39,207 and the median income for a family was $47,879. Males had a median income of $34,800 versus $27,192 for females. The per capita income for the county was $21,493. About 9.9% of families and 14.3% of the population were below the poverty line, including 18.0% of those under age 18 and 13.8% of those age 65 or over. [27]
United States
Illinois 
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