That’s quite a number for a retail store that doesn’t just specialize in cellular phones.
On top of that, it’s worth keeping in mind that there are less than 260 Apple Stores in the US. According to TUAW, “The 11 percent figure shows just how much power Apple has in retail and in its iPhone product.”
There are still retailers selling many more cellphones than Apple. It’s just interesting that Apple manages that while its stores are far less abundant. Also, this is talking cellphone sales, not iPhone sales.