Cigarettes are slowly disappearing from films made for young audiences. A survey by a branch of the non-profit group Breathe California counted nearly 600 instances of tobacco use in last year's top-grossing G, PG and PG-13 movies. That's a more than 70-percent drop from 2005. The survey was featured in the Centers for Disease Control and Prevention's "Morbidity and Mortality Weekly Report." The CDC credits anti-smoking efforts at Time Warner, Disney and Comcast with much of the drop. The agency also says the decrease in on-screen smoking may be part of the reason fewer teens are smoking in real life.