@Sqad - Yeah, but that statistic says pretty much the same thing. Only 10-15% of lung cancers occur in non-smokers.
And Sqad, we can state with a high degree of confidence that smoking causes cancer. Thats what the epidemiology tells us, thats what analysis of whats in the smoke and its mutagenic effect tells us. Thats what Sir Richard Doll was clever enough to notice, all those years ago,when he organised the British Doctors Survey of 40,000 doctors over 20 years, back in the1950s.
Its true that you cannot point to an individual who starts smoking at, say age 16 and state that they will 100% certainly develop lung cancer at age 70, but that is a trivial point. It may very well be that taking up smoking has caused them to develop another disease, such as emphysema, COPD, cardiovascular disease, or any of a number of other cancers that are significantly related to smoking.
You quote from what looks to be about.coms piece on lung cancer, which makes this rather strange point - "the majority of people currently diagnosed with lung cancer do not smoke" - But this is a trivial point. Most of those that comprise this "majority" are former smokers. Only around 1 in 10 of all cases of lung cancer occur in non-smokers.
The same article emphasizes the point -
"Smoking is considered the cause of lung cancer in 90% on men, and 80% of women diagnosed with the disease"
"Men who smoke are 23 times more likely to develop lung cancer than men who do not smoke, and female smokers are 13 times more likely to develop the disease"
What no one is saying is that smoking is the exclusive cause of cancer, although the link between smoking and lung cancer is so strong that it might as well be.
And sure, there will be anecdotal cases of people who smoked 60 a day and have never developed cancer ,but that does not invalidate the epidemiological or scientific/clinical evidence showing smoking as a significant cause.