If AT&T was sweating over losing their iPhone exclusivity back in January, they can rest easy now. According to their first-quarter financials, the carrier sold 5.5 million smartphones -- and 60 percent of them were from Apple.

Engadget is reporting that AT&T’s first-quarter financial results are in for 2011, which most of us have been waiting for to get some idea of how the iPhone’s move to Verizon Wireless may (or may not) impact the once-exclusive carrier. The bottom line is, maybe not so much -- the company is reporting their largest first quarter in history, with a whopping 5.5 million smartphones sold.

So how many of those were iPhones? 3.6 million, according to AT&T, which works out to about 60 percent of all the carrier’s smartphone sales for the first quarter. A full 23 percent of those iPhone sales were actually new to the carrier, suggesting that a mass exodus of customers to rival Verizon isn’t happening quite yet.

AT&T also disclosed that around 40 percent of their smartphone sales were made up of a mix of BlackBerry, Android and Windows Phone 7 devices, although the carrier isn’t breaking that number down quite yet. The company also added 322,000 tablet subscribers to its mix, which we’re betting is mostly comprised of iPad users.

Wireless data revenue increased 16 percent, from $20.13 billion in the year-ago quarter to $23.35 billion this year, while postpaid (i.e., contract) smartphone device sales increased from 22.6 million to 31.5 million year over year -- a nearly 50 percent increase.

The bottom line is that AT&T continues to kick behind and take names, proving that it can share the iPhone with another U.S. carrier just fine, thankyouverymuch.

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