Aircraft perquisites have taken a lot of heat lately, particularly from the SEC when executives’ travel perks aren’t properly disclosed.

Agenda, using data pulled by SEC filings analyzer MyLogIQ, took a closer look at what was disclosed in regulatory filings. As a group, S&P 500 executives spent a collective $39.5 million on air travel in 2017, up from $32.6 million among those executives the year prior.

There were more than 100 executives who spent more than $50,000 in aircraft perks, while almost 200 of the S&P 500 spent between $100,000 and $500,000, filings show.

More than 40% of S&P 500 companies disclosed that they used air travel perks, and of that group, it turns out that Facebook co-founder and CEO Mark Zuckerberg spent more than any other executive. In fact, the $1.5 million in aircraft perks accounted for 17% of his entire compensation plan last year. (His base salary is $1, so his entire compensation package last year fell into the “other compensation” category.)