Everyone knew the day was coming when digital sales would surpass that of physical CDs sale. The question was just when? Well, for Atlantic Records, that time is now.

According to various reports, the label said that more than half -- about 51% -- of its music sales domestically are now from digital sources, which include MP3 and digital album sales from places like iTunes, as well as ringtones.

"We're like a college basketball team on an 18-2 run," Craig Kallman, Atlantic chairman and chief executive, told the New York Times.

It's a little too early to celebrate, though. Experts believe that digital sales aren't growing fast enough to make up for the overall loses labels have taken with the decline in music sales.

NBC Universal CEO Jeff Zucker compares the transition from retail CD sales to digital: "trading analog dollars for digital pennies."

Eight years ago, music sales were at $14.6 billion. This year, the annual sales will be roughly $10.1 billion, and is expected to drop to $9.2 billion by 2013.

So while music sales continue to dwindles, the music industry are trying to find growth through other revenue streams, such as artists' ticket sales and merchandising, otherwise known as 360 deals.

According to Warner Music Group, Atlantic's parent company, digital sales represented 27 percent of its US-based music revenue during the fourth quarter.