The voluntary portion of Medicare in which all persons entitled to the hospital insurance program (Part A) may enroll. The program is financed on a current basis from monthly premiums (presently $6.70) paid by persons insured under the program and a matching amount from Federal general revenues. About 95 percent of eligible people are enrolled. During any calendar year, the program will pay (with certain exceptions) 80 percent of the reasonable charge (as determined by the program) for all covered services after the insured pays a $60 deductible on the costs of such services. Covered services include physician services, home health care (up to 100 visits), medical and other health services, outpatient hospital services, and laboratory, pathology and radiologic services. Any individual over 65 may elect to enroll in Part B. However individuals not eligible for Part A who elect to buy into Part A must also buy into Part B. State welfare agencies may buy Part B coverage for elderly and disabled public assistance recipients and pay the premiums on their behalf. The program contracts with carriers to process claims under the program. The carriers determine amounts to be paid for claims based on reasonable charges. The name. Part B, refers to part B of title XVIII of the Social Security Act, the legislative authority for the program.