The College Board's Advanced Placement program is expanding in U.S. high schools, but as it moves from being a program primarily for elite students, the number of students who fail A.P. exams is growing -- although not as much as the number of students who pass.

About 800,000 public high school seniors in last May's graduating class, or 26.5 percent, took an A.P. exam at some point, twice as many as the class of 2001, the College Board reported.

While the majority of students who take A.P. exams still earn a passing score of 3, 4 or 5, which is enough to earn college credit at many institutions, the share of failing scores has risen with the program's rapid expansion. In 2009, about 43 percent of the 2.3 million A.P. exams taken earned a failing grade of 1 or 2, compared with 39 percent of the 1 million exams taken by the class of 2001.

"Are we getting more 1s and 2s? Absolutely," said Trevor Packer, vice president of the Advanced Placement program. "But are we getting more 3s, 4s and 5s? Even more so. So the question is whether that increase in the percentage of low scores is a reasonable tradeoff for the even larger growth in high scores, and I don't know an educator who wouldn't think it's a good tradeoff to ... give more courses that we know have been good for the few."

Minnesota students, however, are faring better than the national trend, said state Education Commissioner Alice Seagren. More students are taking the tests, but the percentage of those who fail in Minnesota isn't rising. That's likely because teachers and students are going into these classes more prepared, Seagren said.

Last spring, 27,694 Minnesota high school pupils, about 24 percent of the total student population, took an AP test compared to 16,826, or about 16 percent, in 2004. According to the state's number, not only are more students taking the tests, but more students are taking multiple AP tests.

"Minnesota is just knocking things off the charts," Seagren said. "We are doing better than the national average."

Nationwide, the share of seniors who took at least one A.P. exam last year was a third larger than it was for the class of 2004, while the share who got a grade of 3 or higher was about a quarter higher.

Staff writer M.L. Smith contributed to this report.