Some 3.9 billion people are now using the Internet, meaning that for the first time more than half of the global population is online, the United Nations said Friday.

The UN agency for information and communication technologies, ITU, said that by the end of 2018 a full 51.2 percent of people around the world will be using the Internet.

"By the end of 2018, we will surpass the 50/50 milestone for Internet use," ITU chief Houlin Zhou said in a statement.

"This represents an important step towards a more inclusive global information society," he said, adding though that "far too many people around the world are still waiting to reap the benefits of the digital economy."

He called for more support to "technology and business innovation so that the digital revolution leaves no one offline."

According to ITU, the world's richest countries have been showing slow and steady growth in Internet use, which has risen from 51.3 percent of their populations in 2005 to 80.9 percent now.

The gains have meanwhile been more dramatic in developing countries, where 45.3 percent of people are currently online, compared to just 7.7 percent 13 years ago.

Africa has experienced the strongest growth, with a more than 10-fold hike in the number of Internet users over the same period, from 2.1 percent to 24.4 percent, the ITU report showed.

The report also showed that while fixed-line telephone subscriptions continue to dwindle worldwide, to a current level of just 12.4 percent, the number of mobile-cellular telephone subscriptions is now greater than the global population.

And it found that mobile broadband subscriptions have skyrocketed from just four subscriptions per 100 inhabitants in 2007 to 69.3 today.

There are currently a full 5.3 billion active mobile broadband subscriptions worldwide, ITU found.

At the same time, the report said that nearly the entire world population, a full 96 percent, now lives within reach of a mobile cellular network, and 90 percent of people can access the Internet through a 3G or higher speed network.