TORONTO - Ontario may be touting an increase in high school graduation rates but critics say the numbers aren't telling the whole story.

That's because the province is still using a five-year standard to measure graduation rates for its four-year high school program, even though Grade 13 was eliminated in 2003.

Education Minister Kathleen Wynne says the high school graduation rate was 77 per cent last year, up from 75 per cent the year before.

Wynne, when questioned about the numbers, concedes the graduation rate includes students who take five years to complete the four-year high school program.

Wynne says some students come back to increase marks or to access courses that weren't available earlier, and says that's "absolutely within the range of what's acceptable."

The New Democrats say they worry the numbers are designed to make the graduation rates look better than they are.

Wynne couldn't say what the graduation rate was for Ontario students after four years of high school because the Ministry of Education doesn't track that number.

She says using the five-year figure for the graduation rate is a more valid number.

According to Education Ministry figures released Monday, the 77 per cent graduation rate is equivalent to 115,500 students.

The province says the graduation rate was 68 per cent in 2003-04.

Wynne says her goal is to have 85 per cent of students graduating from high school by 2010-11.