Congratulations, you have no clue, just like the vast majority here.I don't use the tests. I type people by evaluating them and comparing which functions lines up with their behavior. I know 3 INTJs. Period.
Even with that assumption you're only looking at one in 10-15 of the members knowing any. For each claiming 2+, if true, you're doubling and tripling the number that don't know any... Again, the claims here are completely impossible.On the other hand, this board is a very biased sample, dominated by intuitives. Intuitives are more likely to be related to and be friends with other intuitives. The list of such factors is very long, which might make this more plausible. Age might be a factor, intelligence might be, even other MBTI characteristics. And let's operate with 1/40 being an INTJ, and not something like 1/100.
Unless they count people they really don't know. Maybe they're like the people I have vaguely known over the years, and they're all claiming they "know an INTJ", which would be pretty comical because aside from online only one person outside my family knows me, and much of my family doesn't to begin with...