Apple's biggest rival when it launches its $10-a-month streaming music service on Tuesday might not be Spotify or Tidal, but piracy.
About a fifth of Internet users around the world continue to regularly access sites offering copyright infringing music, according to the International Federation of the Phonographic Industry.
In the U.S. alone, 20 million people still get music through peer-to-peer file-sharing networks, according to research firm MusicWatch. And newer methods have emerged, such as mobile apps and software that rips audio from YouTube.
Comparatively, just 7.7 million Americans paid for a music subscription service last year.
"It's a tremendous...