First Author:   Arturo Anton Centro de Investigación y Docencia Económicas (CIDE) arturo.anton@cide.edu   Carretera Mexico-Toluca 3655, Col. Lomas de Santa Fe Mexico City, 01210, Mexico   +525557279800(Phone) +525557279800(Fax) http://www.cide.edu/perfil/?IdInvestigador=111 Second Author: Rodolfo Gutierrez Ministry of Finance, Mexico rodolfo_gutierrez@hacienda.gob.mx   Insurgentes Sur 1971 Mexico City, 01020, Mexico   +525536882632(Phone)