1. Sirrine Hall 220F, John E. Walker Department of Economics, College of Business, Clemson University, Clemson, SC 29634, and Faculty of Business and Economics, University of Hong Kong, Pokfulam Road, HKSAR, China (email: )
2. Area of Economics, Faculty of Business and Economics, K.K. Leung Building, University of Hong Kong, Pokfulam Road, HKSAR, China (email: )