Introverted and extroverted are not simply being shy or outgoing, there are many factors that go into determining which one you are. These personality traits are decided upon your characteristics and where you get your energy from but, many people fall somewhere on the scale and are not an exact match to either one.
As an introvert, you are worn out by being in social situations and regain your energy by being alone. People who are introverts prefer being in their mind rather than in the outside world. Introverts are not necessarily shy they just tend to be in their mind. They prefer to have fewer friends that they are comfortable with instead of a large group of acquaintances.
Researchers estimate that introverts can be anywhere from 16 to 50 percent of the population. Careers that fit introverts very well include scientists, writers, artists, and psychologists. These careers fit well due to introverts being more to themselves although, they can make any career work for themselves.
Extroverts, on the other hand, gain energy from being in social situations and large crowds. They become energized from other people and feel welcome in the outside world. They would rather speak aloud rather than being in their own minds. Extroverts prefer having larger groups of friends rather than small groups, unlike introverts.
Researchers estimate that extroverts are anywhere from 50 to 74 percent of the population. They thrive in social situations which makes careers like politics, teaching, and sales great options for them.
Whether you are an introvert, extrovert or in between the world needs these characteristics for certain things and it is important to have these differences between people.
Sources: http://psychcentral.com/blog/archives/2013/09/11/7... , https://www.psychologytoday.com/blog/thrive/201205..., http://www.humanmetrics.com/personality/isfj-caree...