1 The Religious Characteristics of States Dataset Project: Demographics reports the estimates of religious demographics, both country by country and region by region. The RCS was created to fulfill the unmet need for a dataset on the religious dimensions of countries of the world, with the state-year as the unit of observation. It estimates populations and percentages of adherents of 100 religious denominations including second level subdivision within Christianity and Islam. The RCS Data Project would like to acknowledge, recognize, and express our deepest gratitude for the significant contributions of Todd M. Johnson the co-principal investigator of the World Religion Database.