The number of Indiana high schools considered "dropout factories" fell by half between 2002 and 2010, from 30 to 15, according to a report released Monday by a children's advocacy group.

The report released by America's Promise Alliance defined dropout factories as schools that fail to graduate more than 60 percent of students on time. Its report said the number of Indiana students attending dropout factory schools dropped by 19,070 during that time span, the largest decline among Midwest states.

"This report confirms that Indiana is on the right track," said Alex Damron, a spokesman for the Indiana Department of Education. "Increasing our graduation rate has been a key department goal."

The average freshman graduation rate increased from 73.1 percent in 2002 to 75.2 percent in 2010, the report said. But it's still slightly below the national average of 75.5 percent.

The report said Indiana is among 13 states that need to be aggressive in accelerating their graduation rate to reach 90 percent graduation by 2020, which is what the alliance says states should aim for.

The report also found that the number of Indiana students who took at least one Advanced Placement exam during high school increased from 13.1 percent to 31.9 percent from 2001 to 2011.

The research by Johns Hopkins University's Everyone Graduates Center was presented Monday at the Grad Nation summit in Washington.