Thank you for all your wonderful advice on the messed up thread!
The skew might be explicable by something as straightforward as the tendency of certain personality types to take such tests (and publish the results) or it may be that the scoring system itself is flawed - such things are, after all, arbitrary by definition. Nevertheless, it's interesting.
It's reassuring to find that one does have a personality after all. It's sort of like taking one's pulse in the morning - any number one or greater and it's going to be a good day, but fewer than that, well...