Sixteen Maine hospitals rated an “A” rating for safety, according to the Leapfrog Group, a non-profit group run by employers and other large purchasers of health benefits.

Twenty hospitals in the state were ranked in 28 measures in the organization’s annual Hospital Safety Scores released this week, including accidents, physician and nursing staffing, rates of infection, death rates and post-operative outcomes. None of the hospitals received below a “C.”

Among the “A” hospitals in southern Maine were Central Maine Medical Center, Goodall, Mercy, MidCoast, Parkview Adventist, Southern Maine Medical Center, St. Mary’s and York hospitals. Maine Medical Center received a “B” rating.

Leapfrog did not rate critical access hospital, veterans hospitals, rehabilitation facilities or hospitals where not enough data was reported.

The same number of Maine hospitals received “A” ratings in last year’s Leapfrog scores.