Apple is almost certainly about to release the fifth-generation iPhone something in the next few weeks. Still, that doesn’t mean the popularity of the iPhone 4 is waning. In fact, last year’s model is still selling quite well, according to All Things Digital.

First launched in June 2010, the iPhone 4 continues to sell briskly, despite its age and the expected September launch of its successor.

Accordingly, in the first half of 2011, in the U.S. alone, AT&T and Verizon have activated 11.7 million iPhone 4 units. This is just 3.5 million less than AT&T sold in all of 2010.

According to Morgan Keegan analyst Tavis McCourt:

“The iPhone is broadly gaining share in a rather dramatic fashion. This is a product that is 12 months old. Pretty impressive.”

Of course, as All Things Digital reminds us, these numbers shouldn’t be all that surprising. After all, no matter the model, the iPhone has grown in popularity each year since its original launch in 2007.

The handset sold 1.7 million units that first year. In 2010 that number was 40 million. For 2011, so far, that number is 55.2 million.

iPhone Sales

iPhone Sales

Something tells us that number will get significantly larger before the year is over.

What do you think? Leave your comments below.