Part B of Title XVIII of the Act provides for voluntary “supplementary medical insurance” available to most individuals age 65 or over and to disabled individuals who are under age 65 and entitled to hospital insurance. The SMI program is financed by premiums paid by (or for) each individual enrolled in the program, plus contributions from Federal funds. It covers certain physicians' services, outpatient services, home health services, services furnished by rural health clinics (RHCs), Federally qualified health centers (FQHCS), ambulatory surgical centers (ASCs), and comprehensive outpatient rehabilitation facilities (CORFs), and other medical and other health services.