WASHINGTON (AP) — U.S. high schools haven’t shown much improvement in the past four years when it comes to preparing college-ready graduates, according to the Iowa-based nonprofit group that administers the ACT college entrance exam.

The group says only about 40 percent of graduating high school students who took the ACT exam this year show a “strong readiness” for college in most subject areas. Meanwhile, 31 percent of these students aren’t meeting readiness levels in any core subject areas.

According to its findings:

—Asian students outperformed all other ethnic groups in math and science, with 69 percent of Asian students taking the ACT meeting its college readiness standard in math and 57 percent in science.

—African-American students lagged behind significantly in all areas. Only 14 percent of black students taking the ACT test passed the college readiness standard for math, 12 percent in science, 34 percent in English and 19 percent in reading.

—That’s compared to 52 percent of white students who passed the college readiness standard in math, 48 percent in science, 75 percent in English and 56 percent in reading.

— About 29 percent of Hispanics who took the ACT passed the readiness standard in math, 23 percent in science, 47 percent in English and 31 percent in reading.

These levels are about the same as four years ago. The data also shows negligible changes among ethnic groups since 2011, with white and Asian American students still dramatically outperforming other ethnicities.

ACT Chief Executive Officer Jon Whitmore said the education system must do more to prepare students, particularly minorities.