In the year following an eight-cent increase in the federal tax on a pack of cigarettes, sales of cigarettes fell ten percent  In contrast, in the year prior to the tax increase, sales had fallen one percent
The volume of cigarette sales is ttherefore strongly related to the after-tax price of a pack of cigarettes
During the year after the tax increase, there was a greater variety of cigarettes on the market than there had been during the previous year.