https://innocenceproject.org/all-cases/

You can get a rough idea of innocence by exoneration rates + years served. Above-link is just for that one project, which is one of the largest in this arena.

It would also be wise to assume that all exonerations only reflect a small minority of actually innocent people especially when you start factoring in 'crimes' like possession charges or debt (https://www.aclu.org/publications/pound-flesh-criminalizatio...)

A corollary of the “innocent until proven guilty” standard is that there’s just no way to compute such statistics. It’s impossible by design to distinguish between a clearly innocent person and a very suspicious person whose guilt couldn’t quite be proven without looking into the details of their case.