53 



to 9.7% of the market; low tar cigarettes have increased from 

 47% to 51% of the market.) 



3. mrotine/Tar Ratios; 



The ratio of nicotine divided by tar is higher in low tar 

 cigarettes tlian in high tar cigarettes and is higher in ultra low 

 tar cigarettes than in low tar cigarettes. These differences are 

 all statistically significant, at simultaneous levels below .05. 

 The differences remain statistically significant, whether one 

 averages all 10 years of data together or performs an analysis 

 that adjusts for possible effects of year. 



Furthermore, within each of the categories high tar, low 

 tar, and ultra low tar, the ratio of nicotine to tar has been 

 trending upward over the period 1982-91. In each category, the 

 upward trend is statistically significant. 



During this period, the differences among the three 

 categories in nicotine/tar ratio have not changed. The upward 

 trends in the three categories are parallel. 



