Mine is the most common type, ISFJ, at 13% of the population (higher in women, lower in men). I still often feel like I don't fit in, possibly my perception.

This article has a few interesting things to say about supposed link between introversion and mental illness:

https://www.psychologytoday.com/blog...ard-introverts

Tend to agree the extroverts are probably out doing real life things though.