Community News Check out this free community publishing area. See what is happening with non-profits around Alaska. It involves significantly subaverage intellectual functioning accompanied by related limitations in ''adaptive skills,'' such as communication, academics, self care and work. A common estimate is 1.5 percent to 2 percent of the population. That means 5 million people in the United States.
Mental retardation cuts across racial, ethnic and socio-economic lines.
It is more common in boys than girls, by a ratio of about 5 to 4. Degrees of retardation For decades, labels linked to IQ scores were used to describe the extent of an individual's retardation. In recent years, professionals in the field have replaced those categories with a more complex system based largely on how a person is able to function in society. Still the old labels are often used in describing to laymen the degrees of retardation. This includes about 89 percent of all mentally retarded people.