Mobile video traffic is forecast to grow by around 55% annually through to 2021, when it could account for over two-thirds of all mobile data usage. YouTube currently dominates usage and accounts for between 50% to 70% of all video traffic on mobile networks. Netflix accounts for between 10% to 20%. Embedded video in social media and web pages is expected to account for further growth in mobile video. Teenagers not surprisingly have the highest video data consumption, but it is mainly over Wi-Fi networks.

The figures come from the Ericsson Mobility Report. It notes that teens today are streaming natives, as they have no experience of a world without online video streaming. “Viewing is gradually switching from traditional TV to streaming video on smartphones,” the report states.

Between 2011 and 2015, teens increased their television and video viewing at home on smartphones by 85% and nearly halved their time spent watching on a traditional television screen. That is according to Ericsson ConsumerLab research, based on a survey of 9,000 respondents aged 16-59 in nine countries in 2011 and 2015.

According to this survey, the average amount of television viewing among teenagers fell from just over ten to just over five hours a week. Smartphone viewing increased from around two and a half hours to over five hours a week. The implication is that their smartphone video viewing is replacing television viewing.

If we assume that the survey was based on 1,000 respondents in each country and their ages were representative of the national population, the Ericsson study represents the claimed behaviour of around 64 teenagers in the United Kingdom.

As ever, one has to be careful with such self-reported surveys. According to BARB data summarised by Ofcom, viewers aged 16-24 in the United Kingdom watched television for over 16 hours a week in 2014. That is rather more than suggested by the Ericsson respondents.

As the Ericsson report concedes, most mobile video viewing is actually over Wi-Fi networks, but teens are more likely to view streaming video throughout the day, leading to an increase in video viewing over cellular networks.

In fact, teens had the lowest cellular data consumption for video streaming among all age groups, although their overall video data consumption, including both Wi-Fi and cellular, was by far the highest.

The reports concludes that: “Since we are witnessing a generational change, current teens are likely to increase their appetite for cellular data as they grow older — making them the most important group to watch for cellular operators.”

Video accounted for 43% of mobile smartphone data traffic in 2015, based on Ericsson network traffic measurements. On tablets it was 55% of mobile data traffic.

Global mobile data traffic. Source: Ericsson Mobility Report

Ericsson forecasts that global smartphone traffic will increase from just over 4 petabytes per month in 2015 to over 35 petabytes per month in 2020, when video will account for around 70% of mobile data traffic.

However you measure usage, the growth in mobile data traffic is likely to be driven by video, not least because it consumes so much more data than other media and expectations in terms of quality and resolution continue to rise.

The Ericsson Mobility Report is available from the Ericsson web site.