Topics: Can you tell me 10 things about yourself?
Introversion is the state of being predominantly interested in one's own mental self.  Introverts are typically perceived as more reserved or reflective.  Some popular psychologists have characterized introverts as people whose energy tends to expand through reflection and dwindle during interaction.  This is similar to Jung's view, although he focused on mental energy rather than physical energy. Few modern conceptions make this distinction.
Although many people view being introverted or extraverted as mutually exclusive, most contemporary trait theories measure levels of extraversion-introversion as part of a single, continuous dimension of personality, with some scores near one end, and others near the half-way mark.  Ambiversion is falling more or less directly in the middle.   An ambivert is moderately comfortable with groups and social interaction, but also relishes time alone, away from a crowd.
Susan Cain 's 2012 book Quiet: The Power of Introverts in a World That Can't Stop Talking reports that studies indicate 33–50% of the American population are introverts.  Particular subpopulations have higher prevalence, with a 6000-subject MBTI -based survey indicating that 60% of attorneys, and 90% of intellectual property attorneys, are introverts.