According to the article “Why the Rich Don’t Give to Charity” (The Atlantic, April 2013), the poorest Americans give a greater percentage of their income than the richest.
Here’s an excerpt.
“One of the most surprising, and perhaps confounding, facts of charity in America is that the people who can least afford to give are the ones who donate the greatest percentage of their income. In 2011, the wealthiest Americans—those with earnings in the top 20 percent—contributed on average 1.3 percent of their income to charity. By comparison, Americans at the base of the income pyramid—those in the bottom 20 percent—donated 3.2 percent of their income. The relative generosity of lower-income Americans is accentuated by the fact that, unlike middle-class and wealthy donors, most of them cannot take advantage of the charitable tax deduction, because they do not itemize deductions on their income-tax returns.”
I encourage you to read the complete article.