I think it's interesting but to say that it's a credible scientific assessment ? I truly don't think it comes remotely close to being that. For that matter really as useful as I think mbti is, it's really not a "proven" thing itself.
Given all that Australia, really is quite a strange place, in terms of its bio diversity etc. Disconnected from main land masses for so long etc. I'd need to see a lot more compelling evidence, to think there was that kind of disparity in psychological preference types, to accept those figures though.
People, myself included, have a great tendency to believe things we "Like" or want to be correct. Even knowing that doesn't liberate us from the tendency either.