BY the end of of 2010, there will be 5 billion mobile-phone subscriptions globally. A decade ago a mobile-phone user spoke for an average 174 minutes a month, according to the GSM Association, an industry group. By the end of September 2009 that had risen to 288 minutes. There are huge differences in usage among countries. Puerto Ricans are the chattiest, probably because cheap plans include unlimited calls to the American mainland where family and friends are often based. Americans, too, like a good gas, racking up 835 minutes (though some of these are incoming minutes, which are paid for by the subscriber).

AP