TORONTO -- High school graduation rates in Ontario have risen to the highest levels in the province's history.

Figures published today show the four-year rate is now at 78.3 per cent and the five-year rate is 85.5 per cent.

The Ministry of Education is comparing the new numbers to 2004 rates, when 56 per cent of students graduated in four years and 68 per cent graduated in five years.

That's also about the time that Ontario introduced a four-year high school curriculum instead of five, and Premier Kathleen Wynne says it would be a "huge mistake" not to let students take a fifth year because more of them can get their diploma in that time.

The government credits programs such as specialist high skills majors, dual credits and expanded co-operative education for helping to increase the graduation rates.

When the graduation rates are broken down by school board, Catholic ones have consistently higher numbers, but Education Minister Liz Sandals did not offer any possible reasons for that.