1. Department of Economics, Stanford University, Stanford, CA 94305, and National Bureau of Economic Research.
2. Bank of Italy, Via Nazionale 91, 00184, Rome, Italy.
3. Federal Reserve Bank of Cleveland, East 6th and Superior Avenue, Cleveland, OH 44114.
4. Department of Economics, Boston University, 270 Bay Street Road, Boston, MA 02215, and National Bureau of Economic Research.