Final answer:
A corporation's charitable contribution is limited to 10% of its modified taxable income. The limit helps ensure that companies do not reduce their taxable income too much through donations. The trend for corporate income tax as a percentage of GDP has decreased from the 1950s to 2010.
Step-by-step explanation:
The correct answer to the question is 10%. A corporation's charitable contribution is limited to 10% of its modified taxable income. The limit on the charitable contribution deduction serves to ensure that businesses are not excessively reducing their taxable income through donations. It is important to note that the percentage limit can be subject to change; for instance, temporary increases in these limits have happened, such as in response to specific events or during certain years.
As for the historical context provided in the question, the corporate income tax as a percentage of GDP has indeed decreased over time. While not directly related to the limit on charitable contributions, this information highlights changing trends in corporate taxation. In the early 1950s, revenue from corporate income tax was between 5 and 6 percent of GDP, but it dropped to 1.3 percent in 2010.