1. Graduate Institute of Industrial Economics, National Central University, 300 Jhongda Road, Jhongli City, Taoyuan County 32001, Taiwan, Republic of China
2. Department of Economics, National Taiwan University and NBER, 21 Hsu-Chow Road, Taipei 100, Taiwan, Republic of China
3. Center for Risk Analysis, Harvard University and Toulouse School of Economics (LERNA-INRA), 21, allée de Brienne, 31000 Toulouse, France