National reading scores on the SAT college-entrance exam have sunk to their lowest point in 40 years, and the proportion of test takers deemed fully prepared for college remains flat at 43 percent, the test’s sponsors announced Monday morning.

The average score on the exam’s "critical reading" section among this year’s college-bound seniors dropped to 496 points, down 1 point from last year and 34 points from 1972. Each of the SAT’s three sections — critical reading, writing and mathematics — is scored on a range of 200 to 800.

Writing scores also dipped 1 point from last year, to 488, the lowest result since an essay-writing section was added to the test in 2006. The average writing score in that initial year was 497.

SAT math scores remained steady from last year, at an average 514 nationwide. That score, too, was down from a peak of 520, recorded in 2005.

Average SAT reading and writing scores for Hawaii’s college-bound seniors dropped slightly this year, while average scores in math remained unchanged.

Hawaii’s scores continued to lag behind the national average.

Meanwhile, the testing pool in Hawaii grew again this year. Some 9,046 students in the class of 2012 took the college entrance exam, compared with 8,731 in 2011.

For all Hawaii test takers, the average score in critical reading was 478, down 1 point from last year. The average score in writing dropped 2 points, to 467. The average score in math was 500, the same as in 2011.

Public school students, who made up about 67 percent of test takers in the islands, had lower average scores: 456 for reading, 475 for math and 440 for writing.

The highest scorers were from independent, nonreligious private schools: Average scores for the group, made up of 1,682 students, were 531 for reading, 564 for math and 528 for writing.

Girls made up the majority of test takers and outperformed boys in writing. But boys scored better in math (with an average score of 517 versus 487) and reading (482 for boys versus 474 for girls).

Nationwide, the College Board calculated that 43 percent of SAT takers in this year’s freshman class were well prepared for studies at four-year colleges — the same figure as in 2011. That’s based on the percentage of students scoring a combined 1,550 points, an indication they would earn a B- average or better during their first year of college.

"When less than half of kids who want to go to college are prepared to do so, that system is failing," said Gaston Caperton, president of the New York-based College Board, which sponsors the admissions test.