The statistics certainly show that. There's no question that women get elected much more significantly in PR systems than in non-PR systems. That's unquestionable. You could ask, where is the causality? Is it because these countries are more open to women's involvement that they choose proportional elections, so that the causality tends not to go from the electoral system but from the political culture? But the relationship is very strong.
On July 27th, 2016. See this statement in context.