:) I know that because I've read the Foundation's tax returns and audited financial statements that the figures and discussions in Wikipedia are based on.

See also:

https://washingtonpost.com/news/the-intersect/wp/2015/12/02/...

https://dailydot.com/debug/wikipedia-endownemnt-fundraising/

The Foundation has 5 times as much money today as it did at the time of the Washington Post report.