1. Ifo Institute–Leibniz Institute for Economic Research at the University of Munich, Poschingerstr. 5, 81679 Munich, Germany
2. Center for Economic Studies and ifo Institute (CESifo), Munich, Germany
3. Centre for Economic Policy Research (CEPR), London, UK
4. Centre for Competitive Advantage in the Global Economy (CAGE), Warwick, UK
5. Department of Economics, University of Copenhagen, Copenhagen, Denmark
6. Department of Economics, Brown University, Providence, RI, USA
7. Population Studies & Training Center, Brown University, Providence, RI, USA
8. Department of Business and Economics, University of Southern Denmark, Campusvej 55, 5230 Odense M, DK, Denmark