By John Dodge

CHICAGO (CBS) — As of 2012, for every 100,000 Illinois residents, 381 of them were in prison.

In the late 1970s, it was about four times less.

94 per 100,000.

The statewide population in Illinois stood at 12.8 million in 2012, meaning that the state was incarcerating nearly 49,000 people.

The Cook County Department of Corrections, at 26th Street and California Avenue in Chicago, is one of the largest single site county pre-detention facilities in the United States.

Primarily holding prisoners before their trials, the department admits approximately roughly 100,000 detainees annually and averages a daily population of 9,000, according to its website.

On some days, the actual population is around 12,000.

Sheriff Tom Dart has said that up to 3,000 of those inmates have some sort of mental illness and belong in a treatment facility, but not in prison.

In 1978, the state housed 10,725 inmates based on a statewide population of 11.4 million

Watch the prison population explode in Illinois and across the United States, based on this animated map provided on Reddit by Metric Maps, which takes health and population data and turns it into more visual presentations.

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