IQ, the intelligence quotient, is defined as a normal distribution with mean of 100, and a standard deviation of 15. According to James Flynn, people with IQ 70 or less, are mentally retarded, while those with IQ 130 or more, are gifted.
The above image is a simulation of a population of 1 million people, with their IQ’s illustraded by the color scheme. The average IQ, 100, is green, the low IQ’s are blueish, and the higher IQ’s are the ‘warmer’ colors.
As obvious from the image, you are most likely surrounded by very average people.
The graph below shows the proportions of retardedness, normality and giftedness: