In the late 1980s, less than 1% of the world's technologically stored information was in digital format, while it was 94% in 2007, with more than 99% by 2014."The World’s Technological Capacity to Store, Communicate, and Compute Information", especially Supporting online material, Martin Hilbert and Priscila López (2011), Science, 332(6025), 60-65; free access to the article through here: http://www.martinhilbert.net/worldinfocapacity-html/
