Average reading and writing SAT scores for high school students declined to their lowest levels while math results stalled in the exam used for admission at most U.S. colleges. For the class of 2012, the average critical reading score fell 1 point to 496 from a year earlier, the lowest since data became available in 1972, according to a report released today by the New York-based College Board, which administers the test. The average score for writing dropped 1 point to 488, the lowest since writing was added to the exam in 2006. Math results were unchanged at 514. Scores can range from 200 to 800.