Short answers, pulled from the story.
Sir William Petty calculated the first rough estimate of a nation's economic output between 1652 and 1674. This early calculation was developed to prove that landlords were being unfairly taxed during the English Civil War and the conflict between England and the Netherlands.
Congress commissioned economist Simon Kuznets to create a system in 1934 to help the nation understand how to tackle the economic collapse of the 1930s. Kuznets delivered a report titled National Income, 1929, 1932 to the U.S. Senate that introduced the concept of national income accounting.
The production approach sums the outputs of every class of enterprise to arrive at the total. The income approach measures GDP by adding wages, interest, rent, and profits distributed by resident producer units. The expenditure approach calculates the sum of the final uses of goods and services.
The switch from gross national product to gross domestic product in the United States did not occur until 1991. Before this change, the preferred estimate for national economic output was gross national product, which measured production by a country's citizens at home and abroad.
Simon Kuznets warned Congress in 1937 that the metric should not be used as a measure of welfare because economic welfare cannot be adequately measured unless the personal distribution of income is known. He argued that no income measurement undertakes to estimate the reverse side of income, which is the intensity and unpleasantness of effort going into the earning of income.
China officially adopted gross domestic product in 1993 as its indicator of economic performance. This decision marked the abandonment of its previous Marxist-inspired national accounting system and highlighted the global reach of the metric.