Incidence of morbidity is defined by Goskomstat as the number of persons with an initial diagnosis of illness received after a medical visit, classified according to the ICD-9 standard (Table 6). Officially recorded diagnoses depend on help-seeking and utilization behavior, underestimating the prevalence of illness in a generally healthy community. Most studies of morbidity have therefore been based on a limited number of surveys, which have only been conducted on a wide scale since 1992 (Palosuo, 1995; RLMS, 1992).