Follow CBSDFW.COM: Facebook | Twitter

DALLAS (AP) — Texas high school students taking the SAT have posted the lowest scores in more than two decades, showing decreases across the board and mirroring a nationwide decline.

The College Board, which administers the college entrance tests, reports that Texas students in the Class of 2015 averaged 486 on the math section of the test — down nine points from the previous year — and 470 in reading, down six points. A perfect score in each section is 800. Writing scores averaged 454, off seven points.

The Texas scores mirror declines nationwide, although other states haven’t dropped as much.

Lower scores are due at least in part to policies of two dozen districts, including Dallas and Fort Worth, where all upper-class students now take the SAT each year, Texas Education Agency spokeswoman Debbie Ratcliffe said.

“The SAT takers in those districts include not only those who are college-bound, but the whole student population (of juniors and seniors),” she told The Dallas Morning News. “That translates in lower average scores because the more test takers you have, the more scores will decline.”

Texas education officials attributed the declining SAT scores in the state to an increase in the number of minority students taking the exam, the newspaper said. Students from ethnic minorities generally perform worse than white students on standardized achievement tests like the SAT and ACT, the nation’s two leading college entrance exams, they said.

This year, however, Texas students’ performances were overshadowed in a big way by students in California, which has demographics in its student population similar to those in Texas. California students outperformed Texans, on average, by 20 points in math and 25 points in reading, the College Board reported.

Furthermore, while more than 60 percent of seniors in both states took the SAT, California had a higher percentage of low-income students taking the exam as 42.1 percent had their test fee waived. In Texas, 30.4 percent had their fee waived.

The College Board also reported that 41.9 percent of students from this year’s graduating class in the U.S. met the SAT College and Career Readiness Benchmark. In Texas, the figure was 31.8 percent.

High school graduates who reach the benchmark are more likely to enroll in a four-year college and graduate on time than those who do not hit the benchmark. Most minority students continued a pattern of falling short, with only 17.6 percent of the Hispanic and 13.2 percent of the black students in Texas meeting the college-readiness standard.

(© Copyright 2015 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)