Who bought all the iPhone 6 or 6 Plus this quarter?

Remember the time when Tim Cook said that the iPhone 6 and 6 Plus would usher in the "mother of all upgrades"? Turns out that he wasn't that correct with his prediction. During today's conference call for the Q4 2014 financial results, Tim Cook revealed some interesting tidbits about the buyers of the iPhones last quarter (full transcript at SixColors). 

Analyst: What are you seeing in terms of users upgrading iPhones 6 or 6 Plus so far?

Tim Cook: It’s a small fraction, it’s a number that’s barely in the teens
— via SixColors

So some tens of millions of new iPhone users have just entered the Apple ecosystem as of last quarter!