The worldwide rate of mobile phone subscriptions has grown nearly ninefold between 2001 and 2021, according to the ITU analysis.

The subscriptions counted are only those that allow users to make phone calls on their devices—including post-paid and prepaid subscriptions active in the three months before the data was collected. Many of these mobile phones also transmit information over a mobile connection to the internet. But people whose phone connections only connect to the internet, and not their nation's local telephone network, are not included in the analysis. Also excluded are USB modems, public mobile data systems, and radio paging services.

The massive increase in mobile phone subscriptions can be attributed to shifts in both demand and supply. On the demand side, as cellphones occupy greater relevance in daily life and have become necessary for many professions, more people want more devices, and faster, reliable connections at affordable prices have grown.

According to a June 2023 report from Ericsson, the demand for mobile internet bandwidth continues to increase worldwide, almost doubling in the two years from the beginning of 2021 to the start of 2023. On the supply side, technological advances have allowed companies to pack even more capability—functions, sensors, processing power, and data storage—into smartphones, boosting their usefulness.

More efficient components and larger storage capacity—combined with initiatives by organizations such as GSMA to promote smartphone connectivity in developing markets—have helped more people afford more useful cellphones and subscribe to the data and voice services they require.

Countries such as Russia and South Africa report more mobile phone plan sign-ups than their populations because so many people in those countries use more than one phone. In fact, as of late 2022, there were more mobile phones in use around the world than people on the planet, according to the ITU.

Although the number of mobile phone plan subscriptions and smartphone ownership has risen worldwide, the growth in usage is not equally distributed among all countries. In emerging economies, the increase in smartphone ownership is concentrated mainly among those who are young, highly educated, and well-to-do financially, according to a 2019 Pew Research Center report. Nonetheless, the report found that since 2015, more people of all ages have been using smartphones.

Lack of access to smartphones and reliable smartphone operators is a barrier not only to online activity but to the physical world as well: Booking flight tickets, setting up medical appointments, and banking are all increasingly done online.

A lack of mobile phone ownership is a barrier to accessing essential financial services in countries like Ethiopia, according to the World Bank. To help with economic growth and development in the Global South, the bank says it is important to ensure more people have access to reliable smartphones and data infrastructure.

Story editing by Jeff Inglis. Copy editing by Tim Bruns.