Intellectual disability refers to people who have been classified by one or more terms such as developmental disability, developmental delay and mental handicap. Recently, people classified as having ‘mental retardation’ are also being referred as having intellectual disability. Usually, people are considered to have intellectual disability if they have greater difficulty than most people with intellectual and adaptive functioning. These limitations are expressed in the person’s conceptual, social and practical everyday living skills. Intellectual disability is usually diagnosed through the use of standardized tests of adaptive behavior and intelligence.
The precise number of people having intellectual disabilities is not known. However, the American Association on Intellectual and Developmental Disabilities (AAIDD) estimates that roughly 1.5% to 2.5% of the general population have intellectual disability which translates to roughly 4.6 million to 7.7 million people as per the most recent U.S. Census (2011). Over last 30 years, services provided to the people with intellectual disabilities have been changed radically and the institutional care has been replaced by community residential service in several countries.
Source : https://journalhealthcare.com/269035/residential-intellectual-disability-facilities-market-global-industry-insights-trends-analysis-and-forecast-2016-2024/