Clearly the trend that you claim, but hardly a staggering rate of change. Meanwhile, my searches still turn up articles complaining that school administration is male-dominant. I'll be frank: I don't think you have anywhere near enough evidence to make the claims (about causes) you're making.
I found some more specific numbers for Ireland: http://www.irishtimes.com/news/education/the-gender-gap-in-e...
1961: 63% female, 2011: 74% female
Clearly the trend that you claim, but hardly a staggering rate of change. Meanwhile, my searches still turn up articles complaining that school administration is male-dominant. I'll be frank: I don't think you have anywhere near enough evidence to make the claims (about causes) you're making.