The API is limited in what queries you can make*. But someone analysed the whole database a few years ago - see the OGS Player Statistics thread (OGS Player Statistics), and wrote up some results http://nbviewer.jupyter.org/gist/thouis/0f93643a8f14ff802f92
*it won’t let me make queries about ui_class for example - telling me that there is no such field even though there is - so its impossible to get a list of all the bots.