What's the market for emergency care?
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003258:Consumer Behavior; D003625:Data Collection; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006801:Humans; D008389:Marketing of Health Services; D014481:United States