1/3 of Kenyans use M-Pesa, a mobile money transferring platform. M-Pesa recently added support for bitcoin. So while 1/3 of Kenyans have a bitcoin wallet, most of them may not even be aware of this fact.
You may as well say that 2/3 of Americans have a Paypal account because they have a credit card.
I've seen several articles now that heavily imply that this is an official M-Pesa service, which smells a bit scummy to me, if not outright scammy.
Edit: On their blog they explicitly state: "The Kipochi to M-Pesa service is operated by an independent 3rd party company in Kenya and is not directly affiliated with Safaricom the owners of M-Pesa."
This is not an official integration with M-Pesa. M-Pesa users don't automatically have a bitcoin wallet either.
There have been a small handful of good journalists covering the story, but way too many try to fit it into their very tiny world view and invent things that sound cool.
Unfortunately these kinds of sensationalist stories can cause us or anyone else working with Bitcoin problems in the future.