COLUMBIA, Mo. — For a second straight year, SAT scores for the most recent high school graduating class remained at the lowest level in nearly a decade, a trend attributed to a record number of students now taking the test.

The 1.52 million students who took the test is a slight increase from last year but a jump of nearly 30 percent over the past decade. Minority students accounted for 40 percent of test-takers, and 36 percent were the first in their families to attend college. Nearly one in seven had a low enough family income to take the test for free.

“More than ever, the SAT reflects the face of education in this country,” said Gaston Caperton, president of the College Board, which owns the test and released the results Tuesday.

The class of 2008 scored an average of 515 out of a possible 800 points on the math section of the college entrance exam, a performance identical to graduating seniors in the previous year.

Scores in the critical reading component among last spring’s high school seniors also held steady at 502, but the decline over time has been more dramatic: the past two years represent the lowest reading average since 1994, when graduating seniors scored 499.

By comparison, the highest average reading score in recent decades was 530 by the class of 1972, although that score dropped dramatically within five years to near present levels. The latest math average is just five points below the 35-year high of 520, reached three years ago.

Those historical highs are tempered by the test’s more selective reach a generation ago, said Jim Hull, a policy analyst for the Center for Public Education, which is affiliated with the National School Boards Association.

“You only had the best of the best taking the test,” he said. “The SAT has become far more inclusive.”

Average scores also remained constant on the writing portion of the SAT, which was added to the entrance exam in 2006. For the second year in a row, the average score was 494 — a three-point drop from its debut year.

The writing test is still a work in progress, with many colleges waiting for several years of data before factoring that portion into admissions decisions.

But the College Board released data Tuesday suggesting that scores on the newest portion of the exam are the most accurate gauge of first-year success in college. Studies by the University of Georgia and the University of California support the group’s findings, it reported.

Males on average scored four points higher than females on the reading section (504 vs. 500) and 33 points higher on the math test (533 vs. 500), but females on average outscored their counterparts on the writing test, 501 to 488.

Average ACT scores released earlier this month showed a slight decrease, for the class of 2008 — 21.1 compared to 21.2 a year ago, on a scale of 1 to 36. With 1.42 million test-takers, the rival exam still lags behind the more-entrenched SAT, but is growing at a faster rate.

That trend is only likely to continue, said SAT critic Bob Schaeffer of the National Center for Fair and Open Testing, who called the new three-part SAT a “flop.” Nearly 800 colleges now consider the SAT an optional test for admissions, according to the group.