I have the figures for all OECD democracies, meaning Europe and a few other countries. For list proportional representation countries with a legislated gender quota, their legislatures are 32% women. If they have a voluntary party quota with list PR, their legislatures are 29% women. The list PR plus a legislated quota plus a voluntary party quota is 28% women. That suggests to me that if parties are voluntarily putting quotas on and they're legislating quotas, the barriers are considerable.
List PR countries with no quotas are at 30%—