Billing bigger.
D000368:Aged; D005251:Fees, Medical / Q000331:legislation & jurisprudence*; D006076:Government; D006761:Hospitals; D006801:Humans; D007357:Insurance, Physician Services / Q000191:economics*; D006278:Medicare / Q000191:economics*; D010818:Practice Patterns, Physicians'; D014481:United States