As Figure 2.1 illustrates, the history of the distribution of federal revenue by source can be divided into three phases.
• 1789 to 1862: Nearly all of federal revenue was derived from customs duties.
• 1863 to 1914: Approximately half of federal revenue came from customs duties and half from internal revenue sources (such as excise taxes).
• 1915 forward: As the result of the 16th Amendment making the income tax constitutional, the large majority of federal receipts came from internal revenue. For the first time, customs duties were a relatively minor contributor.
A Centennial History of the USITC
U.S. International Trade Commission
https://www.usitc.gov/publications/other/centennial
https://www.usitc.gov/documents/final_centennial_history_508_compliant_v2.pdf