A new survey from consumer ratings firm Nielsen has marked Apple Music as one of the top 10 most popular mobile apps, with some 54.5 average monthly users in the US alone. This also made the service the second-fastest growing app, only behind Facebook Messenger. The figures represent a 26 percent year-over-year rise, although the most recent official figure for paid subscribers was 6.5 million, reported by CEO Tim Cook in October. Facebook was, once again, the top smartphone app, with 126.7 million US users.