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)
Notional amount able to purchase. Hence the notional principal amount is the quantity of the assets and bonds. In the context of an interest rate swap, the notional principal amount is the specified amount on which the exchanged interest payments are based; this could be 8000 US dollars, or 2.7 million pounds sterling, or any other combination of a number and a currency. Each period's rates are multiplied by the notional principal amount to determine the height and currency of each counter-party's payment. A notional principal amount is the amount used as a reference to calculate the amount of interest due on