The parade of wrongly convicted men from Dallas County makes you wonder how many other people suffered the same fate.

Estimates vary, but a new study from Michigan pegs the number at almost 87,000 nationwide from 1989-2003.

University of Michigan law professor Samuel Gross and Michigan State University law professor Barbara O’Brien base their projection on the percentage of people falsely convicted on death row–2.3 percent–to reach that number.

“The main thing we can safely conclude from exonerations of falsely convicted defendants is that there are many other false convictions that we have not discovered,” Mr. Gross said in a press release about the study.

Though tens of thousands may have been wrongly convicted, less than 300 have been exonerated, in large part because DNA evidence is not available in many cases.