Sources: Apple Music has been growing at a monthly rate of 2.6% to 3%, had 28M users in US in February, compared to Spotify's 26M users and growth of 1.5% to 2% (Wall Street Journal)

Wall Street Journal:
Sources: Apple Music has been growing at a monthly rate of 2.6% to 3%, had 28M users in US in February, compared to Spotify's 26M users and growth of 1.5% to 2%  —  Apple's music-streaming service has surpassed Spotify's in paid U.S. subscriptions yet lags its Swedish competitor globally.

from Techmeme http://bit.ly/2YTeeXh