Philanthropy in the U.S. made a comeback in large donations in 2013, with the country's wealthiest donors giving more than $3.4 billion to charity, according to a new count of the top 10 gifts of 2013 by the Chronicle of Philanthropy.

The analysis of the year's top gifts also found more gifts of $100 million or more than in 2012. In 2013, there were 15 publicly announced gifts of at least $100 million, compared with 11 in 2012.

The largest donation of 2013 came from Facebook founder Mark Zuckerberg and his wife, Priscilla Chan, who announced in December that they had given 18 million shares of Facebook stock to the Silicon Valley Community Foundation. The gift was valued at more than $990 million. This was the first time donors under the age of 30 have made the nation's largest philanthropic gift, according to the report.

Colleges and universities were among the primary beneficiaries of some of the biggest donations, the report found.

Nike Inc. co-founder and chairman Philip Knight and his wife, Penelope, made the second largest gift commitment of 2013, pledging $500 million to the Oregon Health and Science University Foundation for cancer research. The university has to match the donation in the next two years to receive the full gift.

The third highest gift of 2013 was a $350 million pledge from Michael Bloomberg to Johns Hopkins University in Baltimore to promote cross-disciplinary studies and undergraduate financial aid.

Other top gifts by American philanthropists were pledged to Yale, Stanford, the University of Michigan, Yeshiva University in New York City, Georgetown University, Columbia Business School, the University of California at San Diego and Tsinghua University in Beijing.

“The fact that we had so many gifts that were $100 million or more is an indication that people are really giving big again,'' and that may continue into 2014, said said of Philanthropy Editor Stacy Palmer. ``People seem more optimistic about the economy, and certainly the strong stock market has propelled a lot of gifts. It looks like it's going to be a better year.”

In 2012, the top gifts totaled $5 billion, but that count included three $1 billion gifts from Warren Buffett to his children's foundations. When those gifts are excluded, the other top gifts of 2012 totaled just $2 billion compared with $3.4 billion in 2013.

However, the wealthiest philanthropists did not give as much in 2013 as before the Great Recession, according to the analysis. In 2007, before the recession, the biggest gifts totaled $4.1 billion.

The chronicle also examined all gifts of $1 million or more. Those gifts totaled $9.6 billion in 2013, compared with $6.1 billion in 2012. (AP)