Public health warnings have been effective in getting more Americans to stop smoking cigarettes, but lung cancer still kills more Americans than any other cancer. The percentage of Americans who smoke has decreased by half over about the last 30 years, from 30% in 1980 to 15% in 2012, but there are still over 150,000 deaths a year. Most cancers are still diagnosed at an advanced stage today. In the long run, quitting smoking will reduce lung cancer deaths 20 years from now; however, in the short run, it's not enough because most lung cancer deaths occur in ex-smokers who remain at risk even after they stop. Smokers need screening for lung cancer annually for 15 years after quitting.