Facebook founder Mark Zuckerberg speaks at Georgetown University in a 'Conversation on Free Expression" in Washington, DC on October 17, 2019.

Facebook spent more than $23 million on security and private air travel for CEO Mark Zuckerberg in 2019, according to a financial filing published on Friday.

That's up from about $20 million spent in 2018 and $9.1 million Facebook spent in 2017. Zuckerberg's annual salary remains $1.

The funds include "approximately $10,463,717" for "costs related to personal security for Zuckerberg at his home and during his personal travel."

It also includes an additional $10 million required to protect him and his family. For comparison, Facebook spent $9.95 million on private security in 2018 and $7.5 million in 2017.

The filing also shows Zuckerberg required $2.95 million for private aircraft costs. He spent $2.59 million on private air travel in 2018 and $1.52 million on it in 2017.

All of the expenses are filed under "Other compensation" for Zuckerberg.

Meanwhile, Facebook's chief operating officer Sheryl Sandberg took home a little over $875,000 in base pay, up from $843,000 in 2018. But, she received a $902,740 bonus, up from $638,000 in 2018, and $19.67 million in stock awards. She received $18.42 million in stock awards in 2018.

Sandberg also required personal security, which cost $4.37 million in 2019, up from $2.9 million in 2018. And her use of private aircraft cost Facebook $1.3 million in 2019 versus $908,677 in 2018. The costs include passenger fees, fuel, crew and catering costs reported by a charter company, Facebook said.

But, in 2019, Facebook reported four straight quarters of sub-30% growth in a row, capping the year off with 24.7% revenue growth during the fourth quarter compared to the same time period in 2018.

Shares of Facebook hit an all-time high on January 29 at $224.20 per share, before dropping with the rest of the market to a new 52-week low on March 18 of $137.10 per share. It closed on Friday at $175.19.