The iPhone 5s is doing pretty well in terms of sales numbers, and has just passed 10 percent usage rate among iPhone models according to mobile analytics firm Mixpanel. That’s a significant milestone, because it means that users are adopting the iPhone 5s at between two and three times the rate they got on board with the iPhone 5. And the iPhone 5c, while trailing the iPhone 5s, is actually doing better than many might expect, too.