As the recession lifted, poor and middle class Americans dug deeper into their wallets to give to charity, even though they were earning less. At the same time, according to a new Chronicle analysis of tax data, wealthy Americans earned more, but the portion of the income they gave to charity declined.

Using the IRS data, The Chronicle was able to track gifts to charity at the state, county, metropolitan-area, and ZIP code levels. The data were for gifts to charity among taxpayers who itemize deductions on their tax forms. It captured $180-billion that was given to charity in 2012, or about 80 percent of the total amount given to charity as tabulated by "Giving USA."

The Chronicle study found that Americans give, on average, about 3 percent of their income to charity, a figure that has not budged significantly for decades. However, that figure belies big differences in giving patterns between the rich and the poor.

The wealthiest Americans—those who earned $200,000 or more—reduced the share of income they gave to charity by 4.6 percent from 2006 to 2012. Meanwhile, Americans who earned less than $100,000 chipped in 4.5 percent more of their income during the same time period. Middle- and lower-income Americans increased the share of income they donated to charity, even as they earned less, on average, than they did six years earlier.

Charities, however, are still looking to high-income donors for support.

Even though wealthier Americans donated a smaller share of their income, the total amount they gave increased by $4.6-billion, to hit $77.5-billion in 2012, using inflation-adjusted dollars.

The Chronicle analysis also found:

  • Residents in Las Vegas, a city hit particularly hard by the recession, increased their giving, when measured as a percentage of adjusted gross income, by 14.9 percent from 2006 to 2012. The increase was the highest in the nation, nearly twice the increase in Jacksonville, Fla., which claimed the number-two spot.
  • Las Vegas's growth helped boost Nevada to the top spot in terms of the state whose residents increased their giving the most—nearly 13 percent from 2006 to 2012. However, because the state was rebounding from a relatively low level of giving in 2006, it placed near the middle of the pack in 2012 in terms of the share of income donated to charity, about 2.6 percent.
  • Following Nevada, the states that experienced the biggest growth in the share of giving were Idaho, Georgia, Connecticut, and Florida.
  • Residents of Utah remain by far the nation's most generous. For every $1,000 they earned, they donated $65.60 to charity. New Hampshire remains the least generous. Those residents gave $17.40 for every $1,000 they earned.
  • Thirty-six of the nation's 50 largest cities experienced declines in their rate of giving. Buffalo suffered the biggest drop—more than 10 percent—in the share of income residents gave to charities.
  • The four top cities as measured by total income—Los Angeles, New York, Philadelphia. and Washington—each experienced declines in how much residents gave as a percentage of their income.
  • Of the 50 largest metropolitan areas, four of the five most generous cities were in the Sun Belt—Memphis, Birmingham, Ala., Atlanta, and Nashville.
  • The 17 most generous states, as measured by share of income donated to charity, voted for Republican presidential nominee Mitt Romney in the 2012 election. Florida, at 18, was the most generous state to vote for Barack Obama.
  • The highest-giving ZIP code was 96015, in California, which includes the town of Canby. The 645 people in that ZIP who filed itemized returns gave a total of $436,000, or 18 percent of their income.

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