T-Mobile USA, the nation's fourth-largest wireless carrier, has sold 540,000 iPhones during the September quarter, comprising between ten and fifteen percent of the telco's total 5.6 million smartphones sold, which includes T-Mobile's prepaid and MetroPCS-branded devices.
By comparison, the #3 Sprint typically reports  iPhone sales comprising as much as 25 percent of all smartphone sold.
For example, Sprint said it sold 1.4 million iPhones during the third quarter of 2013, 40 percent of which went to new customers, versus the five million total smartphones sold...