1. The World Bank Poverty and Equity Global Practice, 1818 H Street, NW, Washington, DC 20433, USA
2. The World Bank Development Research Group, 1818 H Street, NW, Washington, DC 20433, USA
3. Centre for Research on the Economics of the Environment, Agri-food, Transports and Energy (CREATE), Université Laval, Pavillon Paul-Comtois, 2425, rue de l'Agriculture, Québec (QC), G1V 0A6, Canada