The report, released by Health Care for America Now (HCAN), uses data compiled by the American Medical Association to show that 94 percent of the country’s insurance markets are defined as “highly concentrated,” according to Justice Department guidelines. Predictably, that’s led to skyrocketing costs for patients, and monster profits for the big health insurers. Premiums have gone up over the past six years by more than 87 percent, on average, while profits at ten of the largest publicly traded health insurance companies rose 428 percent from 2000 to 2007.