The declines in overall smoking prevalence noted above have led to an increase in the proportion of people who have ever smoked who are now ex-smokers. This proportion, defined by Hill et al as the quit proportion,(5) increased steadily between 1974 and 1992.(4,5,6,6a) Quit proportions have increased at similar rates in both sexes (Table 1.2).(7,8) For further discussion about quitting trends, see Chapter 12, Section 1.