Doing a little informational reading at the CDC website, found this article titled Actual Causes of Death in the United States, 2000. Intro copied below...

"In 2000, the most common actual causes of death in the United States were tobacco (435,000), poor diet and physical inactivity (400,000), alcohol consumption (85,000), microbial agents (e.g., influenza and pneumonia, 75,000), toxic agents (e.g., pollutants and asbestos, 55,000), motor vehicle accidents (43,000), firearms (29,000), sexual behavior (20,000) and illicit use of drugs (17,000)."