1. Massachusetts Institute of Technology, Department of Economics, 50 Memorial Drive, Cambridge MA 02139, and National Bureau of Economic Research.
2. School of International Relations and Pacific Studies, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0519, National Bureau of Economic Research, and Tokyo Center for Economic Research.
3. University of Chicago, Graduate School of Business, 5807 S. Woodlawn Avenue, Chicago, IL, 60637, Federal Reserve Bank of Chicago, and National Bureau of Economic Research.