Laffer curve D. Rockefeller and Henry Ford. While he served as Secretary of the U.S. Treasury Department his wealth peaked at around US$300–US$400 million. Personal income-tax receipts rose from US$719 million in 1921 to over US$1 billion in 1929, an average increase of 4.2% per year over an 8-year period, which supporters attribute to the rate cut. David Hume also expressed similar arguments in his essay "Of Taxes" in 1756, as did fellow Scottish economist Adam Smith, twenty years later. The Democratic party made a similar argument in the 1880s when high revenue from import tariffs raised during the Civil War (1861–1865)
To each according to his contribution as a system whereby the laborer receives the full product of his labor through the elimination of exploitation and accrual of unearned income to a capitalist class. The term means simply that each worker in a socialist society receives compensation and benefits according to the quantity and value of the labor that he or she contributed. This translates into workers of high productivity receiving more wages and benefits than workers of average productivity, and substantially more than workers of low productivity. An extension of this principle could also be made so that the more difficult one's job is—whether this difficulty