We thank Neil Shah and Tarun Pathak from Counterpoint Research for sharing the cell phone data and providing important insights about the market. We thank Jeronimo Callejas for sharing the GSMA Intelligence data. We thank the participants in numerous seminars and conferences for their valuable comments. The authors declare that they have no additional relevant or material financial interests that relate to the research described in this paper. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.