Decatur High School seniors scored above state and national averages on the SAT.

The average composite of mathematics, critical reading and writing scores increased by 52 points from 1518 to 1570, according to the city school system, while the state average increased from 1445 to 1452 and the national average dropped from 1500 to 1498.

Decatur officials said they did best in critical reading, with a 539 average — well below a perfect 800 but 51 points above the state average and 43 points above the nation. The system said it also had a relatively high proportion — 93 percent — of students taking the test.