male smokers: 17%
female smokers: 12%
nonsmokers: 1%If those numbers are accurate, and entirely due to the effects of smoking (not just other lifestyle behaviors more common with smokers, like drinking) that's easily reason enough to quit. But even in the worst case, the fact remains, most smokers will not get cancer.
You can compute the lifetime risk if you have a prior for the lifetime risk of lung cancer (1% in above example), just by multiplying.
Regardless, smoking increases your overall risk pressure along with all of the other risky choices you can make. It's cumulative with the rest of life's choices.