WASHINGTON — The number of young adults without health insurance has dropped significantly, a new survey finds, thanks to a provision of President Barack Obama’s health care law allowing them to stay on their parents’ plans.

The new Gallup poll findings translate to about 1 million more young adults with health insurance.

While the bleak economy has made it hard for young people trying to enter the work force, fewer are being forced to also go without medical care.

A Gallup survey released today finds that the share of adults ages 18 to 25 without health insurance dropped from 28 percent starting last fall to 24.2 percent in the second quarter of this year. That defies the disheartening trend of rising numbers of working-age Americans without coverage.

“While we did not see a drop-off in any other age group, we did see a drop in this age group,” said Frank Newport, Gallup’s polling director.

Public opinion remains divided about Obama’s health care overhaul, but coverage for young adults has proved to be a popular and relatively low-cost benefit that families were eager to sign up for in these days of prolonged school-to-work transitions.

Health and Human Services Secretary Kathleen Sebelius planned her own announcement today about health insurance for young adults. A Census report last week hinted at an increase in coverage.

The new law allows adult children to remain on a parent’s plan until they turn 26, a provision that technically took effect last fall but wasn’t implemented by most workplace health plans until Jan. 1.