SiliconValleyCommunityFoundationLogo650Facebook Co-Founder and CEO Mark Zuckerberg and his wife, Priscilla Chan, were at the top of The Chronicle of Philanthropy’s list of the top 50 donors of 2013, with their gift to the Silicon Valley Community Foundation representing nearly $1 billion of the total of $7.7 billion contributed by the top 50.

The Chronicle of Philanthropy also noted that Zuckerberg and Chan are both under the age of 30, while the median age of donors on the list was 72.5.

In late December, Zuckerberg announced in a Form 4 filing with the Securities and Exchange Commission that he and Chan donated 18 million shares of Facebook class-A common stock to the SVCF, valued at more than $992.2 million.