CHICAGO (CBS) — Illinois, and most notably Cook County, easily leads the nation in the number of people who have been wrongly convicted of a violent crime.

The data comes from the new National Registry of Exonerations, a joint project by the University of Michigan and Northwestern University law schools.

A total of 101 people in Illinois have had their convictions overturned since 1989. That’s 9 percent of the nationwide total of 891 on the list.

Of those 101 people, there have been 78 wrongful convictions in Cook County alone.

That’s more than double the next-closest county: Dallas with 36, followed by Los Angeles with 23.

The top five states:

Illinois 101

New York 88

Texas 84

California 79

Michigan 35

Most of the alleged crimes were for murder and rape, according to a report released by the registry last month.

LIST: Wrongful Convictions By State/County

The most recent case in Illinois involves James Kluppelberg, who was sentenced to life in prison in 1990 for setting a fire that killed a woman and five children in Chicago.

He was released from prison on May 30 after arson evidence was discredited and a witness who claimed Kluppelberg confessed to the crime admitted he had lied.

The list of Cook County convictions includes cases involving disgraced Chicago police commander Jon Burge, who oversaw the alleged torture of several suspects, leading to false confessions.

Those cases include Aaron Patterson, who was sentenced to death in 1989 after being tortured into giving a confession. Patterson was released from prison in 2003.

Patterson has since gone back to prison on federal gun and drug charges.

Cases related to Burge led then Gov. George Ryan place a moratorium on the death penalty and he eventually commuted existing death penalty sentences to life in prison.

The report also found that high population centers have no bearing on the number of wrongful convictions. While Cook County leads the nation, other counties with millions of people—including San Bernardino, Calif., and Fairfax, Va.—have none.

Why are the numbers so high in Illinois?

Aside from the several cases tied to Burge, it could be that Illinois is just better at figuring it out.

According to Michael Helfand’s Chicago Real Law Blog, Northwestern University’s Center for Wrongful Convictions is responsible for uncovering a third of the state’s wrongful convictions.

Nationwide, 12 percent of the wrongful convictions involved death sentences, according to the report.

The report also acknowledges that there are many unknown exonerations. There is no centarlized database for such information and many low-profile cases-–such as those that didn’t involve rape, murder or other violent crimes–were simply concealed from public attention.