I can comfortably say that the majority of people in Japan smoke - I don't know what the statistics are but going by my own statistics - I would say that 80-90% of people over here smoke. Even in Anime for kids you will see characters smoking.
Below is a pic taken at a Japanese Kentucky - the left side is the no smoking section and the right is the smoking section. As you can see - there is no partition whatsoever. Can any body tell me what is the point of having a no smoking section in this food outlet? Some other places are worse - many places don't have no smoking sections but the ones that do may just be a seat next to somebody who smokes.
I know that in the UK it is against the law to have smoke and the preparation of food in the same area (don't know how Benihana gets away with it though) but in Japan it is very common to see your cook smoking and cooking at the same time - smoke and ashes in yer food - lovely.
This has to be the worse thing about living in Japan - I can put up with the earthquakes, tsunamis, typhoons, heat waves etc but having just about everybody smoke around you is rather depressing. But I choose to live in Japan so I try not to complain to much. If you are thinking of living in Japan and hate, loathe the smell of pungent filthy cigarette smoke then be warned - there is really not much you can do about it :-(