1. Department of Economics, Hebrew University of Jerusalem, Jerusalem, Israel 91905 (e-mail: )
2. Department of Economics, Ball State University, 2000 W. University Avenue, Muncie, IN 47306 (e-mail: )
3. Department of Economics, University of Chicago, 1126 E. 59th Street, Chicago, Illinois 60637 (e-mail: )
4. Department of Economics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (e-mail: )
5. The National Center for Chronic and Non-communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Nanwei Road 27, Xicheng District, Beijing, China 100050 (e-mail: )