Smoking was fairly popular on flights well into the 90's, when it was phased out.

I remember checking in flights back then, and that was always the key question, "smoking or non-smoking?". From my hazy memory, on a typical charter flight (so admittedly not a BA scheduled service), say on a 757, of the 40-odd rows, almost always, smoking would be rows 30 back, sometimes even row 26/27. That was always the frustrating thing - the smoking/non-smoking cutover row would move until late into check-in, so ensure most people got their preference. Checking in people who were way down the line inevitably meant you got people at that first row of non-smoking that really didn't want to be there.