Mobile devices account for 60% of video views

"Mobile devices were responsible for 60% of all video views worldwide in Q4 2017 as audiences were more likely to watch programming on a smartphone or tablet than a PC or TV, according to a study by video technology company Ooyala. As more premium sports programming moves online and can be viewed on mobile, this number may top 70% soon.
Smartphones (55%) topped PCs (36%) in Q4 for the percentage of pre-roll ad impressions shown on broadcaster platforms that distribute TV content online. Smartphone pre-roll impressions were highest on publisher platforms at 69%, which Ooyala defines as including news and media organizations. Broadcasters saw mid-roll impressions on smartphones rise to 28% in Q4 from 16% in Q3, while publishers experienced a jump to 51% from 44% for the same periods.
Mobile video plays have increased by about 20% in North America over the past two years as more carriers offered unlimited data plans to attract new users and younger consumers use mobile devices as their primary screens. New, high-tech phone models helped smartphones snag an additional 7.2% of video plays in the past year."

Source:  Data from Ooyala, reported by Mobile Marketer, 15th March 2018

Note - data is taken from sites that Ooyala serves ads to - and does not include YouTube or Netflix for example