Once the highest in the nation, New Jersey's high-school graduation rate takes a big drop.

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Federal data for the class of 2011 shows 83% of seniors graduating in four years, compared to the class of 2010 where 95% of classes in the state graduated in four years, according to the U.S. Department of Education's new graduation rates.

Under the new federal formula, only students who graduate in four years are counted, dropping New Jersey from 8th to 12th in the nation.

"The result is not surprising, it is something that the state Department of Education was expecting," said Lynne Strickland, executive director of the Garden State Coalition of Schools.

"So now they are looking at college freshmen and how many graduate in four years...and in New Jersey there are a number of students who do not graduate in four years and so they would be considered a dropout. For instance, if a parent has a special needs student and they take five or six years to graduate, they might be considered a dropout...mobility is also an issue in this state, we have students who move from district to district and it can't always be tabulated where these students end up."

Stickland said overall the state is still performing well.

"Achievement wise I don't think anything has changed, but you certainly have pockets where you see a higher dropout rate, particularly in urban areas where that needs to be addressed"

State Education Commissioner Chris Cerf says he's not concerned with New Jersey's new place in the rankings.

"I'm only concerned when we're not counting in a consistent, dependable way that allows us to really know what the truth is," Cerf said. "I'm not sure there is any material difference between being in the top 12 versus the top eight. It shows New Jersey is doing extremely well compared to the rest of the nation, and has significant room to improve."