This data came from
http://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/Medicare-Provider-Charge-Data/index
and was referenced in the article
https://www.nytimes.com/2013/05/08/business/hospital-billing-varies-wildly-us-data-shows.html (link no longer active),
as retrieved on 5/8/2013.