Specialists have abandoned emergency rooms in droves, and their exodus is both a cause and a result of the backlogs that plague California hospital emergency rooms. A 2006 survey by the American College of Emergency Physicians found that 73% of emergency departments in the United States had inadequate on-call coverage by specialist physicians. One reason for the flight of specialists from emergency rooms is the surge of patients who have no medical insurance or who use Medi-Cal, which pays some of the lowest rates in the country.