BILLINGS - Doctors say around 15% of people who are diagnosed and die of lung cancer every year, aren't smokers at all; but they are second-hand smokers. Overall, the number of people affected by second hand smoke is down significantly, but not for everyone.

A new Center for Disease Control report shows that in adults who don't light up, the percent exposed to smoke dropped from more than 80% in the 1980's to less than half in recent studies. However in children, the drop is not so dramatic.

The same study found more than 60% of the children they tested had recently been exposed to smoke. Doctors say second-hand smoke raises your risk of lung cancer by 20% and the risk of heart disease by 25%. In children consequences include asthma, ear problems and Sudden Infant Death Syndrome.

"The fact that legislation has been implemented to prevent smoking in public places has helped. Unfortunately children are still exposed at home and they're not as able to have control of their environment." says Billings Clinic Oncologist Tom Purcell.

Numbers are down partially because of people dropping the habit altogether, but also because of bans on smoking in many public places.