Student scores on a popular college entrance exam are down.

FOX News Radio's Tonya J. Powers explains why:

The College Board, the company that gives the SAT exam, says student performance is lagging, continuing a downward trend over the last five years.

A new report says the mean score in reading was 495 - down from 497 the year before... And for math, it was 511, down from 513. The top score in each category is 800.

A record 1.7 million students from the class of 2015 took the SAT -- that's up from 1.6 million last year.

The SAT will roll out a major revamp of the test next year. The idea is to make the exam more representative of what students study in high school and fewer obscure vocabulary words.

Tonya J. Powers, FOX News Radio.