Average scores on the Scholastic Aptitude Test (SAT) rose for the fourth year in a row and marked the largest single-year gain in 22 years, the College Board announced yesterday in New York.

Minority students led the surge, with Mexican-American and Puerto Rican students posting the highest gains, and Asian students still leading the nation in math scores.

Despite the rises, black students lagged more than 100 points behind whites in both reading and math categories. Fewer blacks took the test this year than last year, which experts suggested reflects the fact that fewer blacks are entering college.

The improvements this year ran across all categories, for both males and females and in almost every geographic area, including the District, Maryland and Virginia. But the scores are still a combined total of 74 points behind the all-time high of 1963, when math scores were 502 and verbal was 478. After that year, SAT scores began to slide.

Education Secretary William J. Bennett and College Board President George H. Hanford immediately cited the higher test scores as proof that the nation's educational reform movement has taken root in classrooms across the country.

"Bravo!" Bennett said in a statement. "We begin to see here the impact of the reform movement of the past several years."

Nationally, verbal scores jumped five points, to 431, while math scores climbed four points, to 475.

In the District, the verbal score jumped 13 points this year, to 410, while the math score moved up eight points to 434. In Maryland, students scored 435 on the verbal section, up six points from last year, and 475 on math, up seven points. Virginia students scored 435 on verbal and 473 on math, both increases of seven points over last year.

State-by-state comparisons of SAT scores are somewhat artificial, since in some states -- Mississippi, for example -- only 3 percent of the eligible high school seniors bothered to take it, and they were the best and the brightest of that poor state's struggling school system. With so few Mississippi students taking the test, they scored an unusually high 489 on verbal and 528 on math.

Also, the SAT test is voluntary, usually taken by about a million college-bound students each year. Its results can at best only be used to track the changes in academic performance over the years of those college-bound students who choose to take it.

Still, the SAT test has taken on a symbolic significance as a barometer of America's educational system. When the scores hit rock bottom in 1980, the cry came for a massive overhaul of the public school system and the launching of an educational reform revolution. Now, the progress of that movement -- like the personal success of local school superintendents such as D.C.'s Floretta McKenzie -- is most often measured in terms of how much SAT scores have improved.

President Reagan last year set a goal of stopping the decline from 1963's high in SAT scores by 1990.

This year's good news of the higher scores is coupled with other, more sobering statistics. Almost 2,000 fewer black students this year chose to take the SAT test -- the nation's most widely used college entrance examination -- indicating that black college enrollment for the upcoming year could continue to fall.

Also, the blacks who did take the test, while posting significant gains, still trailed far behind white test-takers. Blacks scored an average of 346 on the verbal portion and 376 on math, while white students outscored them by more than 100 points in both categories. Whites scored 449 verbal and 491 on math.

The disparity between whites and blacks on this key national predictor of academic performance for college-bound students has been a subject of intense debate recently.

"It is certainly reassuring to see that blacks are scoring higher on the SAT," Hanford said, "but it is disheartening to realize that fewer of them appear to be considering going to college."

Other minority groups, while posting gains, still lagged behind white students. For example, Puerto Ricans scored 368 on verbal -- a 10-point gain over 1984 -- but still trailed white students by 81 points. Mexican-Americans scored 383 on verbal, a six-point gain, but that left them 67 points behind whites.

One minority group -- Asians -- scored substantially above all other groups on the math test, averaging 518 compared to 491 for whites.