CHICAGO — Fewer than one in six children who rides a bicycle wears a helmet most of the time but the rate is better than only a decade ago.

A 1991 survey by the U.S. Consumer Product Safety Commission found that about 15 percent of 26.4 million bicyclists under age 15 used helmets more than half the time. It is the only national survey on bicycle helmet use among children.

In the late 1980s, only about one in 20 young cyclists donned protective headgear, said Gregory B. Rodgers, the commission’s lead researcher.

“That showed that a number of the state and local programs that had begun in the late 1980s … were beginning to take hold,” Rodgers said. “And rates of helmet use were rising, and probably they’re higher than that now.”

Survey results were published in the February issue of Pediatrics, based in suburban Chicago.

Angela Mickalide, director of the Washington-based National Safe Kids Campaign, attributed the increase in bicycle-helmet use to education programs, legislation and cheaper helmets. They now cost about $20.

Thirteen states and about 25 communities now require children to use helmets, Mickalide said.

About 250 children die each year in bicycle accidents and another 400,000 are injured seriously enough to require medical attention, she said. Sixty percent of the deaths and about a third of the nonfatal injuries involve the head, she said. Helmets reduce the risk of head injury by 85 percent.

The nationwide survey of 399 children or their parents found that younger children wore helmets more often than older ones — perhaps because parents control younger children better than older ones, Rodgers said.