How many die from medical mistakes in US hospitals?

It seems that every time researchers estimate how often a medical mistake contributes to a hospital patient's death, the numbers come out worse. In 1999, the Institute of Medicine published the famous "To Err Is Human" report, which dropped a bombshell on the medical community by reporting that up to 98,000 people a year die because of mistakes in hospitals. The number was initially disputed, but is now widely accepted by doctors and hospital officials — and quoted ubiquitously in the media. In 2010, the Office of Inspector General for Health and Human Services said that bad hospital care contributed to the deaths of 180,000 patients in Medicare alone in a given year.