1. Department of Economics, Harvard University, Littauer Center 22, 1805 Cambridge Street, Cambridge, MA 02138, and National Bureau of Economic Research (NBER) (e-mail: )
2. Department of Economics, University of Michigan, 611 Tappan Street, 365A Lorch Hall, Ann Arbor, MI 48109 (e-mail: )
3. Banque National de Belgique and Université libre de Bruxelles (ECARES), 50 avenue F.D. Roosevelt, C.P. 114-04, 1050 Bruxelles, Belgique (e-mail: )
4. China Development Bank, 18 fuxingmen neidajie, xichengqu, Beijing, China 100031 (e-mail: )
5. The Wharton School, University of Pennsylvania, 2016 Steinberg Hall-Dietrich Hall, Philadelphia, Pennsylvania 19104, and NBER (e-mail: )
6. Université libre de Bruxelles (ECARES), 50 avenue F.D. Roosevelt, C.P. 114-04, 1050 Bruxelles, Belgium (e-mail: )