We don't keep statistics. We're just not equipped to do that.
In my experience, sitting on various committees and attending various meetings where these issues are discussed, it's always the government's institutions that are best able to gather statistics. Of course, what is kept depends upon what you want to measure. It takes time to gather statistics, and it takes competence with respect to how to do it.
However, I think these issues.... We're talking about people's liberty. If you are thinking that more people should be in jail while presumed innocent on a pretrial basis, and if it's suggested that there is a need for that, I suggest that this justification should not be found on impression. It should be found on demonstrated need as found in statistics.