Actually, if you look at a lot of Startups today (including where I work), they all use Google Apps. How do I know this? Because we partner with a lot of other ones and we all share docs, etc.
Why do you think MS came out with Subscription model and 365? Google was already doing that, and startups went to google instead of the old legacy systems that is Microsoft Office.
And, let me add this to be more clear:
I am referring to Google Apps for Work.
It still doesn't answer my question of 95%. With the industries I work with (Legal, Engineering, Banking, Real Estate) none could be done with Google Apps for Work. It's simply not possible.
95% is hyperbole. It's like saying "50% of businesses don't even need a computer. Everything can be done with paper and calculators". While that can be true, and I know of at least one retail mom/pop business that does just that, it's not 50% of businesses.