This report provides statistics on persons with mental retardation in state-operated residential facilities in the United States. Part I presents population data for fiscal year 1986. The statistics represent aggregated data compiled by each state. Data include number of facilities, average daily population, first admissions, readmissions, releases, deaths, and average cost of care. Part II presents statistics on the characteristics and movement of residents in large and small state-operated residential facilities on June 30, 1985. Part II statistics were gathered through facility surveys of all state-operated residential facilities for persons with mental retardation. Data cover age of residents, diagnostic classification of residents, age distribution by state, level of retardation by state, previous place of residence, and previous placement of readmissions. Part III updates statistics on longitudinal trends in the use of state-operated residential facilities from 1950-1986. Statistics are provided for average daily population, movement patterns, and annual per capita costs. (JDD)