The number of Internet connections will reach 18.9 billion by 2016, up from 10.3 billion in 2011, driven by a proliferation of smartphones, tablets and other handheld devices, according to an annual survey by Cisco Systems Inc.

The number of connections works out to almost 2.5 for each person on Earth in 2016. India is expected to have the fastest rate of Internet traffic growth, followed by Brazil and South Africa, the survey found.

“More and more mobile devices are coming on the network that are causing this growth,” said Doug Webster, a vice- president for San Jose-based Cisco who discussed the report at a news briefing today in Washington.

In 2016, the volume of Internet traffic is expected to be measured for the first time in zettabytes -- or 1 trillion gigabytes, Webster said.

Traffic that year is expected to reach 1.3 zettabytes, or 110 exabytes per month, almost a fourfold increase from about 31 exabytes per month in 2011, the survey found.

That volume will result from the use of more devices, more users, more bandwidth available for transmission and greater use of video for entertainment and business, Webster said.

The Cisco study measures traffic expected to travel over public and private networks, including the Internet, managed IP and mobile data traffic from consumers and business users.