The most common personality type is known to be ISFJ. This is known to be The Defender personality type. This stands for Introverted, Sensing, Feeling, and Judging. This is the type of personality wherein the person would do things depending on how he feels about it. This type of personality is normally very kind-hearted.
They are also warm towards other people although they do not find it easy to speak with other people. This type of personality trait knows what another person is feeling. They are also very much aware of what they are feeling towards something or someone. This personality type does not want to show what he is feeling.
The greatest proportion of people measured by the MBTI fall into the personality type ESFJ, that is, Extraverted, Sensing, Feeling, Judging personalities. This group accounts for over 12% of the population tested. In general, those who prefer Sensing are more frequent in the population than those who prefer Intuition. The percentages falling into each of the 16 types were gained by using the data banks collated between 1972 and 2002, so the sample size would be huge.
Bear in mind that the only factor with very wide acceptance of its validity, reliability (and usefulness) is the Extraversion/Introversion factor. When comparing the MBTI with the Big Five, Extraversion is the most coherent. Therefore, the most common and least common MBTI types may relate more to reliability and validity of the descriptors used than to their occurrence in the population.