Why per capita income of all countries are in dollars?

Per capita income is often expressed in dollars to provide a standardized measure of economic performance that allows for easy comparison between countries. The U.S. dollar serves as a global currency and is widely accepted in international trade, making it a common benchmark. Using dollars helps account for differences in currency values and inflation rates, facilitating clearer assessments of living standards across diverse economies. Additionally, this practice aids in economic research and policy-making by providing a consistent metric.