The rate was the highest since the department started using a new, uniform measure in 2010. Despite the progress, 1 in 5 students still is leaving high school without a diploma.
Iowa topped the state list at 90 per cent. Oregon was at the bottom, 69 per cent. Even lower was the District of Columbia at 62 per cent.
To determine the rate, the number of graduates in a given year is divided by the number of students who enrolled four years earlier. Adjustments are made for transfers.
Growth in high school graduation rates in recent years has been spurred by factors such a greater awareness off the dropout problem and efforts to include graduation rates in accountability measures of how schools are performing, researchers have said. Schools have taken aggressive action such as hiring intervention specialists to keep teenagers in class.
The department did not break down the figures by categories such a race but hopes to do so soon.
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