1. Centers for Disease Control and Prevention WONDER online databases 2013 http://wonder.cdc.gov/
2. Centers for Medicare and Medicaid Services Medicare http://www.medicare.gov/
3. National Health Expenditures; CMS https://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/NationalHealthExpendData/Downloads/highlights.pdf
4. National Health Expenditures CMS http://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/NationalHealthExpendData/NationalHealthAccountsHistorical.html
5. Centers for Medicare & Medicaid Services, Office of the Actuary, National Health Statistics Group https://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/NationalHealthExpendData/NationalHealthAccountsHistorical.html