MONTGOMERY — Alabama’s 89 percent graduation rate is not accurate, but it may be months before the correct numbers are revealed.

A review of the state’s graduation rates by the U.S. Department of Education’s Office of Inspector General shows the state misstated its rates by counting students who received Alabama Occupational Diplomas in its numbers and by not properly overseeing local school systems’ awarding of class credits, resulting in some diplomas that weren’t honestly earned.

“We are accountable to all people of this state and deeply regret the misstating of our graduation rate. We are now undergoing a meticulous review to ensure that all monitoring and data collection is performed with fidelity,” Superintendent of Education Michael Sentance said in a statement.

A state Department of Education spokeswoman said Thursday there won’t be any recalculation of the 2014-15 rates at this time. Malissa Valdes-Hubert said the numbers for the 2015-16 school year are expected to be released in early spring.

The 89 percent rate is just shy of the department’s goal of a 90 percent graduation rate by 2020. The state’s graduation rate was as low as 72 percent in 2012, sparking the department to set improvement goals.

Sentance said the department is establishing an internal audit unit to ensure protocols and procedures are followed.

Gov. Robert Bentley said Sentance briefed him about the findings earlier this week.

“I was alarmed and disappointed to learn the numbers have been reported incorrectly to the U.S. Department of Education, to parents, to legislators and my office,” he said in a statement. “Our Alabama children need and deserve the best education our leaders can offer. I am confident Superintendent Sentence and members of the Board of Education will see to it that happens.”

Rep. Terri Collins, who chairs the House Education Policy Committee, said in a statement that he appreciates the “urgency and candor” in which Sentence has addressed the department’s failure of oversight on the graduation rate issue.

“I’m confident his efforts to reconcile the problem, review procedures and train his staff will be successful in ensuring an oversight of this magnitude does not happen again,” Collins said.