Research (2) Mental retardation (2) Medical care (2) Health (2) Diseases (2) enquête (1) statistiques (1) recherche (1) soins de santé (1) santé (1) âge (1) ordre (1) Aging (1) Methods (1) Statistics (1) Plumbing fixtures (1) Constructivism (Education) (1) Statistics (1) Proportion (1) Population (1) Persons (1) Order (1) Occupations (1) Materials (1) Human beings (1) Literature (1) Impact (1) Health status indicators (1) Happiness (1) Epidemiology (1)