What's the market for HMOs and PPAs?
D003256:Community Participation; D003625:Data Collection; D006279:Health Maintenance Organizations / Q000639:trends*; D006301:Health Services Needs and Demand; D006801:Humans; D007348:Insurance, Health / Q000639:trends*; D011243:Preferred Provider Organizations / Q000639:trends*; D012959:Socioeconomic Factors; D014481:United States