192,756 PREVALENCE Prevalence of selected chronic digestive conditions,United States-July-December 1966 Statistics on prevalence of chronic digesti ve conditions by measures of impact of the conditions and selected demographic characteristics.Based on data collected in the Health Interview Survey during the period July-December 1968, Rockville 1973 U.S.Department of Health, Education,and Welfare 4° s. IV,51, ilustr. Vital and Health Statistics.Data from the national Health Survey. Ser. 10, nr 83.