According to our sister site phonecount.com, 5 billion people now have mobile phones. The billion barrier was broken this week. 5 billion people is 73% penetration. Penetration is the number of phones divided by the number of people, because large number of people have more than 1 phone it is possible to have more than 100% penetration; for example Italy has a penetration of 151%.
Currently every second there are 25 new phones and 4 new people on this planet.