On the number of D you reported you smoked cigarettes during the past 30D, how many cigarettes did you smoke per D, on average
on the number of d you reported you smoked cigarettes during the past 30d, how many cigarettes did you smoke per d, on average
On the number of days you reported you smoked cigarettes during the past 30 days, how many cigarettes did you smoke per day, on average
on the number of days you reported you smoked cigarettes during the past 30 days, how many cigarettes did you smoke per day, on average