I love this kind of stuff, although I usually don't bother with personality tests, etc. Couldn't resist...
Thinking 25% (Hey! I like to think sometimes!
These surveys are useful for a general idea of personality of course, although people may choose answers based on the way they would like to perceive themselves rather than the way they truly are; of course a 70 question survey is not exactly a representative sample to determine one's personality.
(Edit: I believe that the percentage refers to the percentage that one is more of one type than another; for example, I scored 56% more introverted than extroverted!?)