Two out of every three Oregon high school students graduated on time last year, according to figures released Tuesday.

PORTLAND — Two out of every three Oregon high school students graduated on time last year, according to figures released Tuesday.

Oregon high schools posted an on-time graduation rate of just 66 percent for the class of 2010 — just two-tenths of 1 percent better than the previous year, the Oregon Department of Education numbers showed.

In a class that included nearly 50,000 students, 33,000 got diplomas within four years while 4,400 stuck around for a fifth year of high school and about 11,600 dropped out.

"One-third of Oregon high school seniors did not graduate on time last year," said State Superintendent Susan Castillo. "These rates are even more alarming for our poor and minority students."

About 50 percent of black and Native American students graduated on time after four years, while around 55 percent of Hispanic students were on time. But about 76 percent of Asian students graduated on time, well above the statewide average.

The lack of progress at getting students to earn diplomas was widespread, with just three of the state's 10 largest school districts registering improvement in their rates. Those were Salem-Keizer, Beaverton and Medford, which boosted their graduation rates by 2 to 3 percentage points from the class of 2009.

The Oregonian reported that Portland, the state's largest district, posted one of the worst rates in the state with 53.6 percent getting diplomas in four years. About 33 percent, or nearly 1,400 students, dropped out — essentially unchanged from the previous year.

Portland Superintendent Carole Smith expressed disappointment but vowed to dig into the statistics to learn from them and make changes.

Among large school districts, some of the best on-time graduation rates were those in Hillsboro, 77 percent, and Tigard-Tualatin, 81 percent.