There is no threshold at 2.5%. TWO POINT FIVE % gets you GIFTED IQ on the Stanford Binet scale. Mensa starts at 138 or the top two percent - that is classified by many as genius. This is nonsense because it does not include James Woods or Donald Trump, both of whom are top one percenters.
Ace Frehley former lead guitarist of Kiss claims to have a 163 iq and look at him.