On February 6th, 2013 Apple reported that a total of 25 billion songs had been downloaded from its iTunes music store. The previous definitive value was in October 2011 though there was mention of “more than 20 billion” in November. App download totals have recently been much more frequently updated as the following chart shows:
[I estimated 21 billion for the November total.]
The latest two data points point to a surge in iTunes song download rates. Prior to last fall the download rate seemed to be hovering around 10 million songs per day.