This is a very good question. I know there have been studies on MBTI and you can do a cross-reference between MBTI and journal articles, and possibly MBTI demographics. But I think the 1% refers to all people who have taken the MBTI, regardless of their location in the world.
Well, I did found some Australian data..I been unable to find anything else though lol..I guess culture does play a major key role in the way we behave. But as stated before the important thing is not to know how many of us are there but our actual type so we can develop as a person after all we are all individuals and different in our own ways.