Columbia subject headings:
Harvard subject headings:
Health insurance--United States--Statistics
Health maintenance organizations--United States--Statistics.
Medical care, Cost of--United States--Statistics
Medical care--United States--Statistics.
Medical economics--United States.
Medicare--Statistics.
Princeton subject headings:
Health insurance--United States--Statistics.
Health maintenance organizations--United States--Statistics.
Medical care, Cost of--United States--Statistics.
Medical care--United States--Statistics.
Medical economics--United States.
Medicare--Statistics.
Statistics.