1. Department of Economics, Universidad Autonoma de Baja California Sur , La Paz , Mexico
2. Department of Health Promotion, Education, and Behavior, University of South Carolina , Columbia, SC , USA
3. Evaluation and Surveys Research Center, National Institute of Public Health , Cuernavaca , Mexico
4. Epidemiology and Health Services Research Unit, Mexican Institute of Social Security, Cuernavaca , Morelos , Mexico
5. Tobacco Research Department, National Institute of Public Health , Cuernavaca , Mexico