The death rate from lung cancer keeps increasing the fastest among American women, but more men still die from the disease.

The national Centers for Disease Control said Thursday that lung cancer incidence and death rates for 1987 continued a pattern of increasing steadily for women, while fluctuating or holding steady for men.The national lung cancer death rate rose slightly from 1980 to 1987, from 42.5 per 100,000 people to 47.9.

The death rate for men rose by less than 5 deaths per 100,000 people, from 71.6 to 75.0, while the rate for women increased by more than a third, from 20.9 per 100,000 in 1980 to 28.2 in 1987, the CDC said.

The Atlanta-based federal health agency also concluded that the increase among women would continue into the next century.

Lung cancer incidence nationwide increased from a rate of 52.4 per 100,000 people in 1980 to 55.5 in 1986 - the latest year available - and increased faster for women than for men.

Previous studies have said the increasing lung cancer death rate among women may stem from their reduced willingness to quit smoking, as compared to men. But researchers aren't sure that is the only reason.

"I don't think it's fully understood why you have some more rapid growing cancers for some people, and not for others,"said Dr. Ronald Aubert, a CDC epidemiologist.

CDC researchers estimate 85 percent of lung cancer cases are caused by smoking, not counting cases caused by secondhand smoke, Aubert said.

The statistics "are consistent with historically increasing trends in smoking," the Atlanta-based CDC reported.