Echoing decades of anecdotal evidence, a new study of about 2,000 cases of exoneration found that black people are extremely more likely to be wrongfully committed of a crime.

The study, by the National Registry of Exonerations, reviewed cases that happened over the last 30 years throughout the country and found that in addition to black people being wrongfully convicted, it took significantly longer for them to be exonerated than it did any other group, with black people having to wait an average of three years longer.

Samuel Gross, a law professor at the University of Michigan and senior editor of the Registry, said, “It’s no surprise that in this area, as in almost any other that has to do with criminal justice in the United States, race is the big factor.”

The review focused on cases of murder, sexual assault and drug possession and sale—the most common crimes to be exonerated—and found 47 percent of those exonerated were black.

In cases of murder, 50 percent of those exonerated were black, 36 percent white and 12 percent Hispanic. Sexual assault exonerees were 60 percent black, 33 percent white and 6 percent Hispanic. In drug cases, 55 percent of those exonerated were black, 25 percent white and 18 percent Hispanic.

The research team found that the murder rate in the black community contributes to the number of wrongful convictions, but it doesn’t account for the entirety of the disparity. They posit that police misconduct and racial bias also play a definitive role.

The study’s authors say that part of the wrongful conviction rate is that white people have more trouble identifying black people and because of that may serve as poor eyewitnesses to a crime. The review found that that played a role in 79 percent of wrongfully convicted sexual assault cases against black people versus only 51 percent of cases against white people.