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)
Immigration to the United States An internal study by the Department of Health and Human Services under the Trump administration, which was suppressed and not shown to the public, found that refugees to the United States brought in $63 billion more in government revenues than they cost the government. According to labor economist Giovanni Peri, the existing literature suggests that there are no economic reasons why the American labor market could not easily absorb 100,000 Syrian refugees in a year. Refugees integrate more slowly into host countries' labor markets than labor migrants, in part due to the loss and depreciation of human capital and credentials