The statewide average graduation rate for publicly funded high schools rose by more than 2 percentage points from 2009 to 2010, according to the Maine Department of Education.

The percentage of students graduating in four years for the 2009-2010 school year was 82.82 percent.

In Waldo County, Islesboro Central School’s 2010 rate was 100 percent.

According to a press release from the DOE, the overall rate includes 122 public high schools and 11 private high schools with more than 60 percent of students paid for with public funds.

Eighty-eight schools reportedly showed an increase in their respective graduation rates over the previous year, two showed no change, and 43 showed a decrease. Almost half of all the schools, said the report, have a graduation rate lower than 83 percent – the rate required to show Adequate Yearly Progress under the federal No Child Left Behind law.

According to DOE data, all four Waldo County high schools displayed increased graduation rates. Two, though, Mount View High School in Thorndike and Belfast Area High School, had graduation rates lower than 83 percent.

Islesboro, which has 33 students enrolled in grades 9-12, improved from 90.91 percent in 2009 to 100 percent in 2010.

Searsport District High School (RSU 20), with 201 pupils, showed the most dramatic improvement among local schools from 2009 to 2010: going from a rate of 79.25 to 92.31.

Mount View High School (SAD 3), which has 477 students, improved from a rate of 80.49 in 2009 to 82.09 in 2010.

BAHS (RSU 20), which has 634 students enrolled, improved from 81.65 to 81.82.

In addition to Islesboro, three other listed Maine schools had graduation rates of 100 percent — John Bapst in Bangor, Blue Hill Harbor School and North Haven Community School.

“Hopefully what we are seeing with this movement in the positive direction is the result of early efforts at implementing a performance-based educational system,” said Education Commissioner Stephen Bowen.

“I believe, and the governor believes, that by setting rigorous standards and allowing students to move through school based on their mastery of skills – not based on arbitrary timelines and seat time – students will be more engaged, their needs will be more clearly met, and more of them will graduate.

“While the data show a noticeable improvement over the previous year, we can’t be satisfied when nearly one out of five students who enters ninth grade does not graduate in four years.”

This is the second year in which Maine is reporting graduation rates based on the Adjusted Cohort Graduation Rate, or ACGR method, now required of all states by the U.S. Department of Education.

The method calculates the rate for a single “cohort” of students – that is, all the students who entered ninth grade at the same time and who graduated in no more than four years. The 2010 rate can be compared to the rate for 2009, but not previous years, as a different method was used before then.

In the press release, the Maine Department of Education indicated that it supports the use of the new method but warned it paints only part of the picture regarding a school’s success at helping students graduate.

The rate under this method does not include students who graduate in five or six years and does not include students who may come back to school later to earn a GED.