A wide customer base and unlimited data offerings have proven to be a game changer for Verizon, as the wireless carrier now accounts for nearly one-third of all iPhone 4 traffic, according to a recent study from Localytics.

AT&T enjoyed nearly an eight-month time frame as the lone carrier of Apple's popular smartphone. But, according to the report, Verizon is quickly closing the gap, despite only offering the iPhone 4 for about five months.

The report noted that the summer months have proven especially fruitful for Verizon, which has seen its iPhone 4 shares increase from 25.9 percent in May to 32.3 percent in July.

Of course, Verizon recently axed its unlimited data plan offering, moving instead to a tiered structure similar to AT&T's. How this will affect Verizon's standing will be evident in the coming months, but with more than 90 million customers on its network, the carrier should still hold significant sway.

What remains to be seen is which carrier will be dominate when Apple releases the next version of its iPhone. Rumors have circulated for months regarding the handset, and most industry observers seem to agree the smartphone will arrive either in August or September.