NOTE TO READERS: In April 2014, Medicare released 2012 billing data that suppressed payments to medical providers for services they rendered to small numbers of patients. Medicare has since revised its methodology to include additional payments made to providers, and re-released 2012 billing data in June 2015. For this reason, the total payment figures cited in stories published prior to June 2015 may differ from figures cited from June 2015 onward. The original data released can be seen here, and updated figures for 2012, along with 2013 billing data, can be seen here.

A tiny sliver of doctors and other medical providers accounted for an outsize portion of Medicare's 2012 costs, according to an analysis of federal data that lays out details of physicians' billings.

The top 1% of 825,000 individual medical providers accounted for 14% of the $77 billion in billing recorded in the data.

The long-awaited data reveal for the first time how individual medical providers treat America's seniors—and, in some cases, may enrich themselves in the process. Still, there are gaps in the records released by the U.S. about physicians' practice patterns, and doctors' groups said the release of such data leaves innocent physicians open to unfair criticism. (Search Medicare payments to providers in 2012.)

Medicare paid 344 physicians and other health providers more than $3 million each in 2012. Collectively, the 1,000 highest-paid Medicare doctors received $3.05 billion in payments.