Fewer school cafeteria are serving French fries these days. And bake sales? Forget it. Junk food is also less common at school fundraisers, according to a federal study released Friday.

About 19 percent of schools served french fries to students in 2006, down from 40 percent six years earlier, according to the study by the Centers for Disease Control and Prevention.

The percentage of schools that sold cookies or other high-fat baked goods at fundraisers dropped from 67 percent to 54 percent during the six-year period.

And in nearly half of schools, students can select bottled water instead of sugary drinks from school vending machines or snack bars, up from nearly a third of schools in 2000.

But when it comes to encouraging healthy habits, the nation's schools still aren't earning straight As.

Public health officials are cautiously optimistic about the changes.

"We're not satisfied. We still have a long, long way to go, but it is encouraging," said Howell Wechsler, director of the CDC's Division of Adolescent and School Health.

About 90 percent of districts require physical education in all schools. The figure has risen in recent years at the elementary-school level.

Still, in most schools, it's rare for kids to get daily physical education. About two-thirds of elementary schools provide daily recess.

Students need daily exercise, said Jan Harp Domene, president of the national PTA. "Kids that learn this at an early age will practice this into adulthood," she said. "We are growing a whole generation of couch potatoes."

About one-third of U.S. children are overweight, and 17 percent are obese — figures that have been rising.

"We're really at the early phases of trying to counter what right now could be the most pervasive health problem that ever hit the United States — that is obesity in children," said Dr. David Appel, a pediatrician and the director of the Montefiore School Health Program, which provides medical services to school children in New York.

The survey found about a third of schools have a full-time nurse, a figure that has remained steady. About half of schools employ a part-time nurse.

States are increasingly requiring middle- and high-schools to teach sex-education and pregnancy prevention.

Bullying prevention programs also are on the rise. The percentage of elementary and middle schools that participated in programs to prevent bullying increased from 63 percent to 77 percent. The CDC doesn't have that trend data for high schools.

The use of security or surveillance equipment also has increased in schools.

-- Associated Press