1. Department of Economics, Yale University, New Haven, Connecticut 06520, USA;
2. FGV EPGE, Brazilian School of Economics and Finance, Rio de Janeiro, RJ 22250, Brazil
3. National Bureau of Economic Research, Cambridge, Massachusetts 02138, USA
4. Department of Economics, University of Zürich, 8001 Zürich, Switzerland
5. Centre for Economic Policy Research, London EC1V 0DX, United Kingdom