[lprubin]

This article says there are "over 10,000" engineers working at Google:

https://www.forbes.com/sites/quora/2017/07/31/is-working-at-...

This Wikipedia entry says there are 3.87 million professional software engineers in the U.S.:

https://en.wikipedia.org/wiki/Software_engineering_demograph....

So if we're generous and say FAANGs employ 100K engineers, that would be about roughly 2.6% of U.S. software engineers.