1. Department of Economics, University of Mannheim, L7, 3-5, 68131 Mannheim, Germany, and CEPR (email: )
2. Institut d'Anàlisi Econòmica (CSIC), Universitat Autònoma de Barcelona, Campus Bellaterra, 08193 Barcelona, Spain, and ICREA, MOVE, Barcelona GSE, and CEPR (email: )
3. Deutsche Bundesbank, Wilhelm-Epstein-Straße 14, 60431 Frankfurt am Main, Germany (email: )