NEW YORK (CNNMoney) -- For charities hoping to land a big gift from one of America's wealthiest individuals, 2010 was a very bad year.
The 54 most generous donors in America gave only $3.3 billion in 2010, the smallest sum since 2000, according to a ranking compiled by The Chronicle of Philanthropy and Slate magazine.
And not many of those 54 donors are members of the premium tier of net-worth individuals. Of the 400 wealthiest Americans ranked by Forbes magazine, only 17 appeared on this year's list of the most-generous donors.
Noted investor George Soros topped the list with donations of $332 million, followed by media magnate and New York City mayor Michael Bloomberg, with donations of $279.2 million
There are signs the money might not be going to where it's most needed.
According to The Chronicle, nearly half of the 65 gifts of $5 million or more went to colleges or universities, a fact sure to upset those who argue the money would have more utility if applied to other causes.
But not all that money went to the "put my name on a building fund." Some of the gifts were specifically earmarked for student scholarship funds, or clean energy research programs.
Interestingly, no big gifts to colleges came from the under-50 set. Mark Zuckerberg, CEO of Facebook and the world's youngest billionaire, made the top 10 list with his donation of $100 million to the Newark, N.J., school system.
The lack of high-dollar gifts is likely to cause pain as charities work to survive a tough economy.
"The year ahead will be especially tough for nonprofits as governments cut back their spending, and many charities will increasingly rely on big donors to finance vital community operations," Stacy Palmer, The Chronicle's editor, said in a prepared statement.
The decline in giving by the super-wealthy is puzzling given that more than 50 billionaires announced last year they would ultimately devote at least half of their wealth to charity.
Despite the popularity of that commitment, championed by Bill and Melinda Gates and called "the Giving Pledge," only 10 of the couples and individuals who have signed up are on this year's list.
Here are the 10 most generous donors of 2010:
1. George Soros, $332 million
2. Michael R. Bloomberg, $279.2 million
3. T. Denny Sanford, $162.5 million
4. Irwin M. and Joan K. Jacobs, $119.5 million
5. Eli and Edythe L. Broad, $118.3 million
6. Leonard Blavatnik, $117.2 million
7. Frances Lasker Brody, $110 million (bequest)
8. T. Boone Pickens, $101 million
9. Meyer and Renee Luskin, $100.5 million
10. Marc R. Lynne Benioff. $100 million