The intensity of smoking, not just prevalence, is associated with future health consequences. To estimate smoking intensity patterns over time and by age within birth cohorts for California and the remaining United States. Two large population-based surveys with state estimates: National Health Interview Surveys, 1965-1994; and Current Population Survey Tobacco Supplements, 1992-2007. There were 139,176 total respondents for California and 1,662,353 for the remaining United States.