Well I fucked up...
I made a post on hacker news a few weeks ago, I wrote... When DNA matching was introduced, we discovered that at minimum 10% of people on death row were innocent. Death row cases are among the most litigated and examined cases. So, 10% is a reasonable floor, and we're already in double digits. It turns out I'm wrong about the statistic, but the posting window has closed, so I'm going to correct myself here. The actual statistic I confused was this: The exoneration rate is about 10% of the execution rate. For every 1 person exonerated, about 8,2 are executed. https://deathpenaltyinfo.org/facts-and-research/data/death-penalty-census/key-findings