During the US v. Google antitrust trial, University Of Chicago Professor Kevin Murphy revealed the figure while testifying. According to Bloomberg, Google lawyer John Schmidtlein “visibly cringed when Murphy said the number.
Google being the default search engine on all Apple devices and the fact that it spends billions a year to do so, is central to the case. In 2021, they spent $26.3 billion for the privilege, $18 billion of which went to Apple.
Read more on The Verge
Or read on Bloomberg if you can get past the paywall