When the city’s public school graduates threw their caps into the air in June, Suffolk schools had more to celebrate than the passing on of a new set of diplomas.

Based on preliminary reports from the Virginia Department of Education, Suffolk’s high schools are seeing some improvements in their graduation rates.

According to the report, the division saw a 5.4-percentage-point increase in its on-time graduation rate. Additionally, the division’s dropout rate improved by more than 6 percentage points.

In 2008, the division had a 72-percent on-time graduation rate and a dropout rate of nearly 19 percent, meaning that almost one in five ninth-graders would quit school before graduating and that fewer than three-quarters of ninth-graders would earn a diploma within four years.

Both of those numbers improved last year, according to school officials. Last year, the division had a 77.6-percent on-time graduation rate and a 12.6-percent dropout rate.

“This is significant progress to be made in one year,” Liverman said. He added that while the numbers still need work, this is a good start.

Looking at the statistics from one school to another, Nansemond River High School led the way.

In 2008, the school had an on-time graduation rate of nearly 81 percent and a dropout rate of 10.5 percent. In 2009, both of those figures improved; the school had an 86-percent on-time graduation rate and a dropout rate of just 6.3 percent.

Comparatively, King’s Fork High School had a 67.6-percent on-time graduation rate and a 20.8-percent dropout rate in 2008; for the 2009 graduating class, those numbers improved to a 71.9-percent on-time graduation rate and a 16.5-percent dropout rate.

Lakeland High School saw the biggest improvements of all the schools.

In 2008, the school had a 23.7-percent dropout rate, which improved to 13.8 percent in 2009.

Additionally, the school went from a 69-percent on-time graduation rate in 2008 to a 76.2-percent rate last year.

Liverman said these numbers are just preliminary, and the official state report will be released Oct. 20.