Washington (CNN) -- Some of the worst high schools in the United States are getting better, according to a study released Tuesday.
Quoting numbers from the Department of Education, the report says that the number of "dropout factories" or high schools that graduated 60% or fewer of their students in four years, decreased by 112 between 2008 and 2009.
That still leaves more than 1,600 schools in the nation meeting "dropout factory" criteria, according to the "Building a Grad Nation" report, but it states, "it is noteworthy that urban and rural schools that had proven to be the most challenging to reform are showing, at least in some locales, signs of forward movement."
The largest improvement was seen in rural schools, with a 15.5% decline in the number of low-performing schools in those areas.
Leading the pack, California and South Carolina each had 25 fewer low performing high schools in 2009 than they did the previous year. Georgia and New York, on the other hand, actually had the largest increases in the number of low performing schools in their states.
The report was released to coincide with the Grad Nation summit in Washington, in which experts are looking at ways to increase high school graduation rates.
Vice President Joe Biden spoke to the group on Tuesday, and promoted the administration's goal to increase the proportion of college graduates to the largest in the world by 2020.
"Right now about 40% of our young adults have a college degree," Biden said. "In order to meet that goal by 2020 of being number one in the world, we have to raise that to 60% of young adults having completed a college degree. That's a significant task."
Biden said that success in college is determined in high school.
"The single best predictor of successful college completion -- notwithstanding the myths out there -- is not family income, is not parental education," he said. "It is not race, although you can trace it back to high school arguably on that. What is it? It's how academically rigorous a student's high school curriculum is."
At a field hearing in Utica, New York, Rep. John Kline, R-Minnesota, drew a direct connection between success in the classroom and in the workplace.
"The evidence overwhelmingly suggests that individuals who fail to advance in their education are more likely to be unemployed and earn lower wages," Kline said.
At the Grad Nation conference, Biden held up a new publication by the Department of Education called "College Completion Tool Kit" which lists strategies for governors to use to increase college graduation numbers in their states. Some of the recommendations include aligning high school graduation standards with college entrance standards, and making it easier for college students to transfer between schools.
The "Building a Grad Nation" report was sponsored by the America's Promise Alliance, Civic Enterprises and Johns Hopkins University's Everyone Graduates Center. It can be found online at http://www.americaspromise.org/.