What happened to mild and moderate mental retardation?
D004185:Disability Evaluation; D006233:Persons with Disabilities; D004495:Education of Persons with Intellectual Disabilities / Q000639:trends*; D006801:Humans; D008607:Intellectual Disability / Q000534:rehabilitation; D007360:Intelligence; D011632:Public Assistance / Q000331:legislation & jurisprudence; D012106:Research; D014481:United States