Thanks to the RIAA, via Digital Music News, we can witness 40 years of music sales in 40 seconds or less. The pie chart GIF below starts in 1973 and ends in 2012, and is chopped up according to the song and album sales methods of the day. Witness the beginning of the digital revolution in 2004, when the nearly sated Pac-Man that was the CD slowly got its maw pried open by a boom of new mediums. It's also pretty cool to see vinyl come back into the picture. (Keep fighting the good fight, Record Store Day.) It should be noted that the size of the pie does not correlate with the amount of money made overall in a single year.