In its quarterly earnings call, Apple revealed that it now has 13 million paying subscribers for its Apple Music streaming service, showing an impressive pace of growth in expanding its user base.

The figure represents an increase of 2 million customers since February, when executives of the company revealed that it had surpassed the mark of 11 million subscribers.

In January, it was previously reported that Apple Music was able to reach 10 million paying subscribers over its first six months since its launch in July last year. To put the feat in perspective, major music streaming service rival Spotify was not able to reach the figure of 10 million paying users until May 2014, which is eight years since the service was launched in 2006.

Earlier in the year, Spotify claimed that is was nearing the mark of 30 million paying subscribers. This places the Apple Music rival significantly ahead of Apple's offering, but with Apple Music's rapid growth, it might not take long before it catches up to the number of paying subscribers of Spotify.

Tidal, another rival music service owned by Jay-Z, has so far only amassed 3 million subscribers, a number which will not likely see a significant increase despite it having exclusive streaming rights to "Lemonade," Beyonce's new album. Pandora, another competing service, only had 4 million paying subscribers as of October last year.

Among the factors that have recently contributed to the growth of Apple Music include exclusive content coming to the service from artists such as The 1975, Future and Drake, along with endorsements by high-profile celebrities. It also helps that the app is installed by default on over a billion iDevices, while being deeply integrated into iTunes.

Apple Music grew from the Beats Music streaming service, which was eventually shut down by Apple after it purchased Beats for $3 billion a couple of years ago.