Digital music is now responsible for more than half of all music sales in the US, according to figures recently released by Nielsen. It's a milestone for the industry as it's the first time that digital sales have topped physical stores with regards to album sales. If we had to venture a guess, digital shows no signs of slowing down anytime soon.

When looking at things on a deeper level, we see that digital album sales jumped by 14 percent in 2012, totaling 118 million units. Digital album sales accounted for roughly 37 percent of all albums sold last year, up from 31 percent in 2011.

Physical album sales, on the other hand, didn't fare as well. Album sales dropped 12.8 percent which led to overall album sales falling 4.4 percent year to year. Music sales overall were up 3.1 percent thanks largely in part to digital single sales led by Gotye's "Somebody That I Used to Know" and Carly Rae Jepsen's "Call Me Maybe" with 6.8 million downloads and 6.5 million downloads, respectively.

Overall, 1.3 billion tracks were sold in the US last year, the most ever for a single year. This was good for a 5.1 percent increase in sales, we're told. As you can see, digital music continues to be a key growth element within the music industry.

Surprisingly enough, sales of vinyl albums were up 17.7 percent in 2011, totaling 4.6 million. This figure hardly scratches the surface compared to digital and disc sales but it's impressive nevertheless considering how long vinyl has been around.