One example of a measure that placed a high tax on large incomes is the Revenue Act of 1913 in the United States. This act introduced the modern federal income tax system and included a progressive tax structure, which meant that higher incomes were subject to higher tax rates. The highest tax rate under this act was set at 7% for incomes above $500,000 (equivalent to about $13 million in today's dollars). This act was a significant shift towards a more progressive tax system in the United States.