Many scholars will point out there is no way to really know the total number of lynchings, because so many were unreported.
I am convinced that there is no way to know how many have been assaulted or murdered without cause when stopped by police. We know it has happened. We have no way to know how often or how pervasive the problem has been. It keeps looking worse and worse.
It is impossible to have useful statistics for criminal behaviors which have been hushed up and covered up for decades or centuries.