Earlier quoted context omitted.
remember that MBTIs have no evidence base - they can be helpful in allowing someone to "see" jobs they might be happier in, as they did for me, but they don't necessarily measure anything statistically significant about a personality.
Sure - they're not the be-all answer to everything, but I've found them helpful in (re)assessing myself lately. I found much more static-ness in my IQ over the last 30+ years. I was actually surprised at how consistent it was over decades and various tests (and, dare I say, slightly disappointed).
http://en.wikipedia.org/wiki/IQ_classification
that has actually recently been updated with reliable sources. Some of the comments below this comment of yours make guesses about IQ tests that can be checked against the sources by referring to that article.