18. During the past 30 days, on the days you smoked, how many cigarettes did you smoke per day?
[] This question does not apply to me because I have not done this during the past 30 days.
[] Less than 1 cigarette per day
[] 1 cigarette per day
[] 2 to 5 cigarettes per day
[] 6 to 10 cigarettes per day
[] 11 to 20 cigarettes per day
[] 21 or more cigarettes per day