As a 60% Introvert (according to the MBTI - always somewhere
   around there) - I can completely relate! ( My definition of
   introvert: After spending time with people, an introvert needs
   to recharge their batteries by being alone for a bit. An
   extrovert, just gets more and more energy when around people).

   The percentage thing helps because yeah, sometimes I get energy
   when I'm around people. But it depends on the people and the
   situation. Usually I gotta vanish for a few minutes someplace
   now and again when I'm around people for extended periods of
   time.