Since its debut five years ago Monday, Apple's iTunes Store has sold more than 4 billion songs and accounts for approximately 70 percent of digital music sold worldwide, Wired reports.

But according to a new study from InStat, it's projected that Apple will account for a stunning 28 percent of all music sold globally by 2012. That's not small change, either, since the firm also predicts 40 percent of music sold will be of the digital variety.

We wouldn't call these "dark clouds on the horizon," because that's cliche, but the story said that soon Apple may need to rethink its iTunes strategy—especially since its partners in the music business are looking for ways to give its competition an unnatural advantage.

"Apple is under pressure from the four major labels to change its pricing model to a tiered pricing structure," said Susan Kevorkian, an IDC audio analyst, in the article. "The way the labels are pressuring Apple is by withholding DRM-free downloads from the service... [while] cultivating other online music services, most notably Amazon's MP3 downloads store."