Int. J. Environ. Res. Public Health 2009, 6 612 29%]/36%=19%) within this occupational category. Among manual workers, there was also a significant decrease in smoking prevalence, but it occurred later, between 2003 and 2005, from 44% to 37% (p<0.001). After this decrease, between 2005 and 2008, as the cigarette price only increased slightly, the smoking prevalence among manual workers came back to its initial level (from 37% in 2005 to 43% in 2008, p<0.001). Finally, smoking prevalence amongst unemployed people showed a somewhat erratic pattern over time, but it was higher in 2008 (50%) than in 2000 (44%) (p<0.001). Moreover, when compared to manual workers and unemployed people, executive managers and professional occupations were significantly less likely to smoke during the whole period, with a widening gap (36% versus 44% and 45% in 2000, 29% versus 43% and 50% in 2008). Finally, the smoking prevalence was very similar for manual workers and the unemployed in 2000, and it was higher for the unemployed in 2008 (but the difference was not statistically significant, due to the small number of manual workers and unemployed people in the 2008 sample, respectively n=299 and n=98). Figure 1. Trends in smoking prevalence for executive managers and professional occupations, manual workers and the unemployed, 2000-2008, France. This increasing social differentiation of smoking could be partly due to shifts in the socio- demographic composition of occupational categories. Nevertheless, between 2000 and 2008 the mean age did not change within the unemployed group (36 years-old) and among manual workers (38 years- old), and varied only slightly for executive managers and professional occupations (from 41 to 42 years-old). Regarding gender, 82% of manual workers were men in both 2000 and 2008, and this proportion only decreased slightly (from 65% to 62%) among executive managers and professional occupations. Finally, the proportion of men increased among unemployed respondents (41% in 2000,