There is a huge and very strong correlation between less smoking and lower lung cancer rates. You claimed otherwise, that's what I was referring to. Of course some people still get it without smoking.
Now smoking has dropped significantly and smoking indoors and in many public spaces is banned. But the non-smoker lung cancer rates don't appear to be dropping accordingly.
Did we replace the 2nd hand smoke with some other cancer causing particulates? Or were we wrong about 2nd hand smoke and there was something else in our environment the whole time?
It could be replacement of some sort - car usage has gone up continuously, and we inhale a lot of exhaust in cities. Maybe it was exhaust the whole time?
I’d also be interested to see the data you’re referencing on lung cancer rates in non-smokers.