In the first quarter, Apple Retail Stores accounted for one-fifth of all sales growth by publicly traded retailers in the U.S., according to a report by Scott Patterson of USA Today.

In the first three months of 2011, Apple’s U.S. retail sales rose by $4.6 billion, an 80 percent increase from a year ago.

Of those sales, 40 percent were related to the iPhone. Sales of the handset (which, it should be noted, arrived at Verizon in February) grew 113 percent from the previous year.

Following Apple, the biggest chunk of U.S. sales growth occurred at Amazon.com and Wal-Mart Stores.

In total, U.S. retail sales increased $23.2 billion in the first quarter.

While these numbers are great news for Apple (and its shareholders), they also suggest continued problems in the U.S. economy as a whole.

According to David Berman, the retail sales expert who released these numbers, they are a “reflection of poor sales among most retailers.”

Nonetheless, we wouldn’t be surprised to see Apple’s amazing numbers continue. After all, the iPhone 5 is expected very soon.

What do you think? Leave your comments below.