1. Norwegian University of Life Sciences, School of Economics and Business, Christian Magnus Falsens vei 18, 1433 Ås, Norway (email: )
2. Department of Economics and CEBI, University of Copenhagen, Øster Farimagsgade 5, 1353 Copenhagen, Denmark (email: )
3. University of California, Berkeley, 530 Evans Hall #3880, Berkeley, CA 94720, and NBER (email: )