This paper uses 16 smoking supplements from different years of the National Health Interview Survey between 1978 and 2000 to construct smoking histories going back before 1950. A similar method, based on cohort reconstruction, has been used in the sociological and medical literature with U.S. and Canadian data (Ferrence 1989; Harris 1983; United States Government 1980).

Since 1978 the smoking questionnaire in the National Health Interview Survey includes questions about the age at which individuals started smoking cigarettes, if they ever started, and about how long ago they stopped, if they did so. Using the year at which individuals started smoking and the year at which they stopped, I constructed 373,738 smoking histories of adults aged 25 and above at the time of the interview.<sup>5</sup> To make sure that the education variable is not time sensitive, and given that most people will have reached their definitive education level by age 25, I have sampled only individuals aged 25 and above.

# **_2.2 Smoking Prevalence by Education Category, 1940–2000_**

Figure 1 shows how the general smoking prevalence evolved in the United States from 1940 to 2000. The years 1950 (consensus in medical journals), 1964 (first Surgeon General Report) and 1970 (clear health warning on the packages) are benchmarks in the gradual diffusion of the information about the health consequences of tobacco. Smoking prevalence in the population aged 25 and above was 37.7 percent in 1940 and reached a peak of 45.9 percent in 1957, before the publication of the Surgeon General’s report. After that, it steadily decreased and reached 24.6 percent in 2000.

Figure 2 breaks down the data used in figure 1 in four educational groups: individuals with less than a high school degree, high school graduates, individuals with some undergraduate education and finally college graduates together with individuals having studied at the graduate level. It is worth mentioning that each point on figure 2 is estimated from at least 1,000 observations. In 1940 individuals with less than a high school degree are the least likely to smoke (35.8 percent). The smoking prevalence for the three other education categories is all close to 40 percent (39.4, 40.8, and 40.4 respectively). By 2000 there is a clear negative gradient between educational achievement and smoking

> 5 To estimate the smoking prevalence in any year, I created a dummy variable for every individual who interviewed after or during that year and was aged 25 and above in that year. The dummy takes the value zero if the individual never smoked, started after that year or stopped before it. It takes the value 1 if the individual smoked during that year. In the 1983, 1985, 1990, 1991 and 1994 surveys, no questions about the age at which individuals started smoking were included. Given that, in the other 11 surveys, 93.3 percent of the respondents who ever started smoking had started by age 25, and since I only sampled individuals aged 25 and above, I considered every person to have ever smoked in these five surveys has having started by age 25. Individuals might stop smoking for a certain period and then resume. A few surveys (1978, 1979, 1980, 1990, 1991, 1992) included questions about temporary smoking cessation, but since in 86.2 percent of the cases the period of temporary smoking cessation was not longer than one year, I have for simplicity ignored it and decided to use only the starting year and the year of definitive cessation.

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