RICHMOND—More than 83 percent of high school students statewide graduated on time in 2009, according to data released Tuesday by the Virginia Department of Education.

Meanwhile, the on-time graduation rate improved overall in the Isle of Wight County Schools division, and the dropout rate fell at both of the division’s high schools.

Last week the superintendents for the public school divisions in Southampton County and Franklin announced their preliminary figures, which remained unchanged when the official tallies came out Tuesday.

The VDOE reported that 83.2 percent of students who started the ninth grade during the 2005-06 school year, and were essentially considered the Class of 2009, received a diploma within four years. The rate improved one percentage point from last year.

“A one-point increase in the graduation rate represents nearly 1,000 additional young men and women who earned diplomas and are ready for post-secondary education or entry-level employment,” Superintendent of Public Instruction Patricia I. Wright said in a written statement Tuesday.

Wright added, “Building a long-term trend of rising graduation rates will require a continued student-by-student approach by educators, as well as the sustained involvement of parents and strong partnerships with community institutions.”

There were also fewer dropouts statewide in 2009. The statewide dropout rate fell to 7.93 percent, down from 8.7 percent last year.

As a division, Isle of Wight County Schools graduated 83.61 percent of its high school students on time in 2009, slightly above the state average.

While the on-time graduation rate at Smithfield High School posted a big gain — going up to 85.9 percent and exceeding the statewide average — the rate fell slightly at Windsor High School to 78.3 percent. The on-time graduation rates at the schools last year were 80.7 and 79.9 percent, respectively.

“We are pleased by the progress our students and teachers are making,” Isle of Wight County Schools Superintendent Dr. Michael McPherson said. “The gains in our graduation rates reflect the hard work demonstrated each and every day by our dedicated staff.”

Dropout rates fell to 9 percent at Smithfield and 14 percent at Windsor. Last year the dropout rates were 11 percent at Smithfield and 14.9 percent at Windsor.

Both Southampton and Franklin made significant improvements in their respective on-time graduation rates. Southampton High School graduated 80 percent of its students on time in 2009 and Franklin High School graduated 71.5 percent. Those rates improved by 4.8 and 6.6 percent from the 2008 figures, respectively.

Franklin High School’s dropout rate fell 4.7 percent to 19 percent overall, while Southampton High School’s dropout rate posted a slight increase to 12.4 percent; it was 11.1 percent in 2008.

This is the second consecutive year Virginia has tracked students from year to year to determine the on-time graduation rate using a formula endorsed by the National Governors Association.

The rate is calculated using data from the state’s Educational Information Management System, which tracked the Class of 2009 — also called a cohort, or statistical group — for the last four years. Students were each assigned a unique tracking number, and the state then looked at the records of students who entered the ninth grade in 2005 to see if they graduated on time in 2009.

Students are factored into a school’s on-time graduation rate when they transfer into a school, but are subtracted from the rate if they transfer out.

“With policy direction from the Board of Education, and the support of the governor and General Assembly, Virginia is setting a national standard for accuracy and transparency in the reporting of graduation rates,” Board of Education President Mark E. Emblidge said.

There are 324 high schools in Virginia. According to the VDOE, 187 had graduation rates higher than the state’s 83.2 percent, two schools matched the state and 135 were lower. Sixty-five school divisions had graduation rates higher than the state, 65 divisions had rates that were lower, and one division’s graduation rate was the same as the state rate.

Meanwhile the state reported that dropout rates of 184 schools were lower than the state rate of 7.9 percent, and two schools had dropout rates that were comparable. The dropout rates of 138 schools exceeded the state rate. The number of high schools with dropout rates of five percent or less was 106, and 39 schools had dropout rates of 15 percent or higher.

The VDOE also found that 67 school divisions had dropout rates lower than the state, one school division’s dropout rate was the same, and 63 divisions had rates that were higher. Thirty school divisions had dropout rates of five percent or less, and 13 divisions had dropout rates above 15 percent.