The number of high school seniors taking Advanced Placement exams is steadily rising, but a significant gap persists with lack of exam-taking among African-American students, according to a report released Wednesday by the College Board.

The report, “7th Annual AP Report to the Nation,” shows that the raw numbers of students taking at least one AP exam has grown from 432,343 for the Class of 2001 to 853,314 for the Class of 2010.

The number of students who scored a 3 or better on the exam has also grown, from 277,865 to 508,818 during the same years, although the overall percentage has dropped from just over 64 percent to just under 60 percent. A score of 3 means a student is “qualified” to receive college credit in that subject, although experts say colleges are increasingly requiring a score of 4 or better in order to earn college credit.

Still, the increase in the number of students taking the AP exam — just one of several indicators of college readiness — is a welcome development, even if the percentage of students scoring a 3 or better has gone down.

Observers say the lower percentage of students scoring at least a 3 suggests that AP exams are being offered to broader groups of students than in the past.

“I certainly think that there’s a broader base of students who are getting access to AP, and that is good,” says Lisa Sohmer, director of college counseling at Garden School in Jackson Heights, N.Y., and a former board member of the National Association for College Admission Counseling. “I still think there are a lot of schools where AP is not available, and it’s important for people to understand that while AP is valuable, it does not define the quality of a student’s high school experience.”

Bob Schaeffer, public education director at FairTest, a group that advocates for equality in educational testing, voiced similar concerns, arguing that AP exams are still a “relatively minor factor in secondary education in this country.”