But for cell phones it's a different story. Here the United States is a laggard, with 77.4 subscribers per 100 people. The place to see the potential for worldwide cell phone use is Europe, where every country but Turkey exceeds the penetration of the United States. Italy, where many people have multiple subscriptions, is the European champ, with 135.1 cellphone subscribers per 100 people. Hong Kong exceeds even that, with 135.3. The overall global average is 41.6 subscribers per 100 people. The world's 2.75 billion mobile phone users are growing in number at an annual rate of 27%.