mainstream economics in the past 200 years has a completely different feature from classical economics, that is, it has systematic economic indicators. , which is also a sign of the progress of economics research and promotes the widespread application of mathematics and statistics in this field. The United States has made a major contribution to this. The well-known GDP (gross domestic product) is an invention of the American economics community. 　　The development from basically no statistical data to an economic indicator system with GDP as the core is not a simple process of formula derivation. It is accompanied by profound changes in society, politics, economy and culture. 　　”Pricing Progress” by…