1. School of Economics and Management, Tsinghua University, Beijing 100084, China (email: )
2. China Center for Economic Research, National School of Development, Peking University, Beijing 100871, China (email: )
3. School of Finance, Renmin University of China, Beijing 100872, China (email: )
4. World Bank, the Research Group, 1818 H Street, NW, Washington, DC 20433 (email: )