AUGUSTA — Even as graduation rates fell at half of Maine’s high schools last year, the state’s overall graduation rate increased, from 82.8 percent to 83.8 percent.

“One percent is considered real movement, especially because we’ve done it two years in a row,” said Department of Education spokesman David Connerty-Marin.

Maine’s high school graduation rate, which counts students who graduate within four years of entering high school, was 80.4 percent in 2009. Students who take more than four years to finish or who get diplomas through adult education are counted as dropouts.

From 2010 to last year, graduation rates fell for 66 Maine high schools, increased for 64 and stayed the same for two.

From 2009 to last year, 90 of the 132 schools increased their graduation rates.

One school that’s apparently on the right track is Messalonskee High School in Oakland, where the graduation rate has increased from 84.2 percent in 2009 to 88 percent in 2010 to 90.2 percent last year.

“We’re not perfect — we have a long way to go,” said Superintendent Gary Smith. “But we really try to work with each and every student and understand if there’s some issues in respect to graduation — how can we all kind of come together and help this student reach that goal?”

Because of federal mandates, Maine changed the way it calculates graduation rates in 2009, so the rates for the last three years cannot be compared with earlier data.

“We are glad to see an increase and that Maine appears to remain ahead of the national average,” said Education Commissioner Stephen Bowen in a news release. “We still have considerable work to do.”

The graduation rate for low-income students increased about 2 percentage points but remained much lower than the rate for the general population, at 72.7 percent.

Girls are graduating on time more often than boys: 86.5 percent to 81.3 percent.

Graduation rates are higher at Maine’s town academies, which are private schools that are subject to some state requirements because at least 60 percent of their students are publicly funded. The graduation rate for those schools was 91.8 percent, including students whose parents pay tuition.

At public high schools, the graduation rate was 83.1 percent, up from 82 percent in 2010.

Easton Junior-Senior High School, North Haven Community School and Vinalhaven School achieved 100 percent graduation rates among their small 2011 graduating classes.

Among regular high school programs, Wiscasset High School had the lowest graduation rate in 2011, at 61.8 percent. The rate was 78.2 percent in 2009.

Maranacook Community High School in Readfield also had a sharp decline in the past two years, from 92.7 percent in 2009 to 76 percent in 2011.

Superintendent Rich Abramson said that is probably because of the inclusion of students from Phoenix House Academy of Maine. Maranacook’s staff works with the teenagers in the residential substance-abuse program, and they are counted as Maranacook students for state subsidy and other data collection.

Abramson said nearly every Maranacook student leaves with a diploma, even if it’s a year or two late or completed through adult education.

Kennebec Journal Staff Writer Susan McMillan can be contacted at 621-5645 or at: smcmillan@mainetoday.com