The Recording Industry Association of America just released its 2011 sales figures yesterday (PDF here), and there was a surprising bit of good news in them.Total U.S. music sales actually grew for the first time since 2004. They were up 0.2%, just topping $7 billion. The reason: digital sales were up 9.2% during the year, and physical sales (mostly CDs) dropped only 7.7%, which is smaller than in recent years.Digital made up more than half of revenues for the first time ever.