The poor and middle class have increased the percentage of their income they give to charity, while the wealthy are giving a smaller percentage, according to a report from the Chronicle of Philanthropy released last week.

Between 2006 and 2012, the wealthiest Americans, those who earned $200,000 or more, reduced the share of their income they gave to charity by 4.6 percent. During the same time, Americans who earned less than $100,000, including poor and middle-class families with two working adults, donated 4.5 percent more of their income, the Chronicle’s analysis of IRS data shows.

But wealthier Americans have more money than low-income people at their disposal. The total the richest donated rose by $4.6 billion after adjusting for inflation, reaching $77.5 billion in 2012, even though the share of income they gave was shrinking. Those who earned less than $100,000 gave $57.3 billion, the Chronicle says.

Residents of Utah remain the nation’s most generous, as previous studies have shown. For every $1,000 they earned, they donated $65.60 to charity. As in previous studies, New Hampshire residents remain the least generous, giving $17.40 for every $1,000 they earned, according to the Chronicle.

Nevada was the state with the fastest-growing rate of donations as a share of income, jumping nearly 13 percent from 2006 to 2012. Residents of the state donated 2.7 percent of their income to charity. North Dakota saw the biggest decline in giving. Residents reduced the share of income they donated by nearly 16 percent, contributing $24 for every $1,000 earned on average.