Far greater than you would expect, I think. This is anecdotal, but we're an admittedly small company (~20-25 employees) and all of our interactions with other companies (clients) are either direct line-to-line or if we do a conference call, we all call in over the phone. Many of the companies who send us WebEx or join.me or Hangouts Meet or whatever invites only send the phone number even, not even bothering to give us a link (and if you go to the room manually in your browser, you're the only one actually connected via computer)