The average level of high-income countries in the world. Universal education means that the state implements a certain degree of general education for all school-age children. The popularization of education is the average level of high-income countries in the world, and the popularization of education at all levels has reached or exceeded the average level of middle-and high-income countries, among which preschool education and compulsory education have reached the average level of high-income countries in the world, and higher education has entered the popularization stage.