WASHINGTON – Walking nervously across the stage in an oversized gown, a boxy cap tilting off your head and shaking the principal’s hand while grabbing your high school diploma is becoming a rite of passage for more and more American students, according to a study released Monday showing the national high school graduation rate has hit its highest point in U.S. history.

The nation’s average high school graduation rate topped 80 percent in 2012, according to the analysis of federal data produced by America’s Promise Alliance, a foundation created by former Secretary of State Colin Powell. The foundation called for increasing the rate to 90 percent by 2020.

Iowa had the highest average graduation rate, with 89 percent, while Wisconsin finished closely behind, graduating 88 percent of its students. According to the data, Nevada had the lowest average rate with 63 percent.

But despite the good news of a new record in national graduation, the annual report also brought some bad news.

The report found that a disparity between graduation rates of white students compared with minority students continued to plague many states.

In Wisconsin, 92 percent of white students are graduating versus 64 percent of black students and 74 percent of Hispanic students. In New York, there is a 24 percentage point difference between the graduation rates of white students compared with Hispanics and blacks.

Christian D’Andrea, an education reform policy analyst at the John K. MacIver Institute for Public Policy in Madison, Wis., said in a telephone interview that the achievement gap has always been a big problem in the state. But educators are making moves to fix it – creating a task force and putting together a list of reforms to raise minority grad rates.

Officials of Opportunity Nation, a group of nonprofits dedicated to educational equality, noted that racial disparities are not the only challenge.

“The zip code you’re born in should not determine your destiny,” said Mark Edwards, executive director of Opportunity Nation.

Students from low-income families have to overcome a huge hurdle – their graduation rates range from 58 to 85 percent compared with the national average of 80 percent.

“This is an issue of equity and we have to change the opportunity equation,” said Education Secretary Arne Duncan, adding that in the coming years, America’s schools will be majority minorities.

“Dropping out is a symptom of other problems,” Duncan said. “We need to solve those outside issues.”

But even for those who do graduate, those high school diplomas don’t necessarily mean they are ready for success in the real world.

That’s why Rick Hess, director of education policy studies at the conservative American Enterprise Institute, believes such data should be approached with caution – and viewed as a piece of the larger picture in terms of student success.

“It’s possible to increase high school graduation rates by dropping standards,” Hess said, so the figures should be considered alongside test scores and whether high school graduates complete college or enter the workforce.

Hess noted that an intense focus on dropout prevention programs in recent years keeps teens from leaving school, “but that doesn’t mean they’re necessarily learning anything.”

In Wisconsin, D’Andrea said that educators found more and more students needing remediation once they got to college.

“It suggests a lot of high school students don’t have the tools they need to thrive in college,” D’Andrea said. “But there’s been a recent callback to raise standards.”

Duncan echoed experts and acknowledged that raising graduation rates alone is not good enough.

“It’s not just graduating from high school. It is graduating college and career ready,” Duncan said.

“High school graduation may once have been a finish line,” he said. “Now it’s only the beginning.”