82.4% of lung cancer deaths are attributable to smoking.
"The Health Consequences of Smoking—50 Years of Progress. A Report of the Surgeon General." U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health. Smoking-Attributable Morbidity, Mortality, and Economic Costs. 2014. Report.