A very interesting table. I'm not sure what your definition of active players is though. I make your list 72 players, and OER lists 78 with at least one point. It probably doesn't matter anyway as I suspect only EWS has anything to compare.
The one that raised my eyebrows immediately was Fran with 'just' 58. Hopefully she can get a proper biggie in the next year or so.
I'm guessing, without looking further at all, that there is a good number of players for whom their biggest ranking win has been on grass and I suppose that grass is relatively less of that opportunity for Fran.