No teacher hired by Gwinnett County Public Schools during the past five years has received a raise. No teacher employed by Clayton County Schools got one during that time, either.

School district officials have long complained that the absence of state funding, combined with an increasingly poor student population and a shrinking property tax base have made for a perfect financial storm.

Now, districts have a detailed foul weather report from the Georgia Budget and Policy Institute, a left-leaning policy group that has thrown some eye-popping numbers into the debate about school funding.

Over the past decade, Georgia didn’t give public school districts $7.6 billion that they were due under a state formula, a study from GBPI has found. That happened while the recession clobbered governments and the percentage of Georgia students who qualified for school meal assistance climbed from 45 percent to 60 percent. Educators argue that, for a variety of reasons, it takes more money to educate poor students than it does to educate affluent ones.

Eight of the 10 districts that lost out on the most money over the past decade were in metro Atlanta, with districts in Gwinnett County ($739 million), Cobb County ($491 million) and DeKalb County ($444 million) leading the way.

The state’s complicated funding formula, called the Quality Basic Education formula, directs funding to districts based on the number and needs of their students. Metro Atlanta districts are among the largest in the state. But GBPI’s study also found that financial pain is acutely felt in rural districts, which do not have large property tax bases that can be tapped to make up for an absence of state funds.

“This report holds no surprises for local school districts,” Gwinnett Superintendent J. Alvin Wilbanks said. “We fully understand the impact the recession has had on the state budget. However, we also know that we cannot continue to provide a quality and effective education without additional revenue.”

Legislators, wrestling with declining state revenues, provided districts with $7.6 billion less than QBE called for them to receive over the past decade.

Claire Suggs, the senior education policy analyst who compiled the report, said GBPI hopes its report provides a set of sobering truths to state legislators, whose unwillingness to raise taxes or find other ways to direct more money to schools forces local school boards to pass property tax rate hikes.

“Raising revenues, that’s going to have to be addressed if we want to have the results we expect,” Suggs said. “(State legislators) are going to have to wrestle with that.”

Georgia’s Republican-controlled Legislature is unlikely to raise taxes. Many GOP legislators campaigned on smaller government and less taxes and are loath to publicly break those promises.

About half of the money school districts get comes from the state. The federal government provides about 10 percent, with local property taxes accounting for the rest.

Local school boards have no control over state or federal funding, but they have repeatedly raised local property tax rates in recent years, GBPI found.

Over the past decade, 138 school districts in Georgia raised property tax rates.

For a couple of reasons, however, local property tax money isn’t a cure-all.

First, nearly 75 percent of school districts in Georgia saw their local property tax base shrink over the past decade, as the recession battered the value of real estate and reduced district revenues that were based on assessed property value. And second, state law caps how much property tax money most districts can extract.

The Clayton County system has been at its limit of 20 mills for the past five years, said the district’s chief financial officer, Ken Thompson.

That has meant forgoing teacher raises in Clayton, leaving some positions open, increasing class sizes and going from 180 instructional days per school year to 175 days, Thompson said.

“We try to keep the impact as far away from students as we can,” Thompson said.

But with most districts now having fewer than 180 instructional days per school year, state Sen. Jason Carter, D-Decatur, said students are being hurt.

“There’s no doubt you’re getting less learning,” he said. “At some point, the disinvestment catches up with you. What we’re doing is eating our seed corn. You can’t eat your seed corn and not have it catch up with you.”

State Sen. Lindsey Tippins, the Marietta Republican who chairs the Senate’s Education and Youth Committee, agreed.

“If you ask me if education is underfunded in the state of Georgia, I’d say, ‘Absolutely,’” Tippins said. “There are people who say, ‘Well, education will need to just get used to this.’ I hope that’s not the case. We are recovering. Now is the time to reassess. We need to put all of the money in public education that we possibly can.”