The College Board, a nonprofit that oversees Advanced Placement exams, found in its annual report that 1 in 4 students taking the exams are from low-income backgrounds.
More than 22,000 schools now offer AP courses, an all-time high.
Disparities remain in exam scores, however; a smaller proportion of black and American Indian students in particular scored at least a 3 on the exam, the level that confers college credit.