1. Department of Statistics and Informatics, Federal Rural University of Pernambuco, Recife, PE 52171-900, Brazil
2. Department of Economics and Informatics, Federal Rural University of Pernambuco, Serra Talhada, PE 56909-535, Brazil
3. School of Public Policy and Government, Getulio Vargas Foundation (EPPG/FGV), Brasilia, DF, Brazil