"Simon Kuznets is best known for his studies of national income and its components. Prior to World War I, measures of GNP were rough guesses, at best. No government agency collected data to compute GNP, and no private economic researcher did so systematically, either. Kuznets changed all that. With work that began in the 1930s and stretched over decades, Kuznets computed national income back to 1869. He broke it down by industry, by final product, and by use. He also measured the distribution of income between rich and poor."