By Jordan Valinsky, CNN Business

(CNN) -- Jeff and MacKenzie Bezos donated more money to charity last year than anyone else in the world, according to The Chronicle of Philanthropy.

The Amazon CEO and his soon-to-be-ex wife donated $2 billion to boost nonprofits that help homeless families. The donations were made under their "Bezos Day One Fund," which started in September 2018.

The couple announced their divorce last month but said they remain "partners in ventures and projects."

The top 50 donors on The Chronicle of Philanthropy list donated roughly 50% less than last year. Overall donations from the world's 50 top donors dropped from $14.7 billion in 2017 to $7.8 billion in 2018.

Billionaire businessman Michael Bloomberg, who gave $767 million to several causes, donated the second most money to charity last year. Pierre and Pam Omidyar gave the third most with $392 million in donations, and Blackstone CEO Stephen Schwarzman gave $390 million in donations.

Bill and Melinda Gates, who topped the list in 2017 with $4.8 billion, dropped all the way to No. 12 in 2018. They made $138 million in charitable donations. Mark Zuckerberg and Priscilla Chan, who donated $2 billion in 2017 — the second most money donated that year — dropped to No. 7 in 2018, with $213.6 million in donations.

The Chronicle of Philanthropy notes that its list is not comprehensive.

"Some billionaires don't regularly make the Philanthropy 50 because they donate infrequently in very large amounts. Others may give anonymously or choose not to disclose their charitable giving publicly or to the Chronicle. These 21 donors gave more than $5.5 billion in 2018," according to the publication.