There are almost as many mobile phone subscriptions in the world as people, a United Nations telecom agency has said.
A report by the International Telecommunication Union (ITU) said there were about six billion subscriptions at the end of 2011.
There are nearly seven billion people on Earth.
Almost one billion subscriptions were in China, the study found.
The report, called Measuring the Information Society 2012, looked at 155 countries, assessing their access to and use of information and communication technology (ICT).
The head of the agency's data division, Susan Teltscher, said: "We count Sim cards, not the number of devices or people, so if one person has two Sim cards in one device, it counts as two subscriptions; and we count monthly subscriptions as well."
Sim cards used in a tablet or to access the internet on a laptop computer had not been taken into account, she added.
The Geneva-based agency also said almost two billion people - about one-third of the world's population - had been internet users by the end of 2011.
In developed countries, 70% of the population was online, compared with 24% in developing regions, it said.
There were almost twice as many mobile broadband subscriptions globally as fixed broadband ones, said the agency.
The director of ITU's Telecommunication Development Bureau, Brahima Sanou, said: "The surge in numbers of mobile-broadband subscriptions in developing countries has brought the internet to a multitude of new users.
"But despite the downward trend, prices remain relatively high in many low-income countries.
"For mobile broadband to replicate the mobile-cellular miracle and bring more people from developing countries online, 3G network coverage has to be extended and prices have to go down even further."
On 14 October, leading names in the ICT industry will gather at ITU Telecom World 2012 - a global networking and knowledge-sharing event in Dubai.
Some 300 global leaders are expected to attend the conference, including heads of state, ministers, regulators, academics, and representatives of such companies as Cisco, Kaspersky Lab, Huawei, Verizon, Qualcomm, Ericsson.