Walgreen's

(WAG)

fourth-quarter sales rose 16% from a year ago, thanks to double-digit growth in prescription-drug revenue.

The drugstore chain earned $412 million, or 41 cents a share, in the fourth quarter, up from last year's $329 million and 32 cents a share.

Sales advanced to $12.2 billion in the quarter from $10.5 billion a year ago. Same-store revenue rose 9.7%, and prescription sales climbed 18% in the fourth quarter. On average, analysts expected a profit of 41 cents and a top line of nearly $12 billion.

"We remain committed to organic store growth while carefully considering unique acquisition opportunities that are a solid fit with our store base and culture," said CEO and President Jeff Rein. "We're on track to reach our goal of operating 7,000 stores in 2010."