Mobile is expected to overtake the desktop as the top internet advertising medium by 2017. ZenithOptimedia forecasts that globally, advertisers in 2017 will spend $99.3 billion on mobile internet advertising, compared to $97.4 billion spent on desktops. The media service firm’s previous prediction had mobile taking the top spot in 2018, but updated its timetable following extremely fast growth in the sector.

In 2015, mobile internet advertising grew 95 percent and is forecast to turn in growth rates of 46 percent in 2016 and 29 percent in both 2017 and 2018. In contrast, desktop advertising peaked at $98.9 billion in 2014 and slipped 0.2 percent in 2015 to $98.7 billion. The desktop segment is expected to continue its decline in 2016, by 0.9 percent, and in 2017 and 2018 at 0.4 percent and 6 percent, respectively. By 2018, desktop advertising will account for 42 percent of all internet advertising, compared to mobile’s 58 percent.

Mobile advertising remains behind television and ZenithOptimedia expects it to remain so for at least the next few years. It forecasts mobile to account for $127.8 billion by 2018 compared to television’s $192.2 billion.

To read more on the trends behind this shift, click here.