Religiosity is defined as the importance of religion in all aspects of life. The definition is operationalized into a robust measure by aggregating 14 items from the World Values Surveys. Religiosity falls by 50 \% when countries pass through the transition from being underdeveloped to becoming a developed one. A formal test shows that long-run causality is predominantly from income to religiosity. The transition slope is robust to measurement error and composition of the country sample. The empirical macro relation is rationalized by some micro theory: Most components of the demand for religious goods are reduced by rising income. Churches supply religious goods directly and through three additional channels: education, healthcare, and social security. Rising income caused churches to lose control over the additional channels.