I'd expect the top decile number to be heavily driven by public companies, though. Especially with the recent IPOs, you're now looking at Google, Apple, Facebook, Lyft, Uber, etc all of which pay a huge portion of their comp in stock.

They're not worthless in the sense that employees put value on them and take less salary as a result. Or in other words, they could get a higher salary (+guaranteed RSU) from a larger company but chose not to.

So from an employee point of view not having them counted is disingenuous.