What percentage of Jews in medieval Europe were money lenders?

I’m currently reading Abraham’s Heirs by Leonard Glick, and he explains how medieval Ashkenazi Jews were pushed out of other occupations and only allowed to be money lenders. This made me wonder how many Jews in each community were actually engaged in this business. Were all members of the Jewish community (or at least all adult males) supporting themselves as money lenders? The book says most Jewish communities had, at most, only a few hundred members. It’s not clear to me how many households that would be. But it still seems like a lot more lenders than would be needed for the average medieval town or city.