Awesome graph showing the relative number of computing devices shipped over the past 40 years for each operating system. After a couple decades of Windows PC dominance, smartphones have just completely changed the landscape. Android has one of the most absurd growth curves for any OS imaginable. Interestingly, iPhone's alone are about equal with Windows PC shipments, which actually includes Chrome OS as well.
For all the people touting the death of the iPad, its helpful to be aware that twice as many iPads are shipping as Macs, so its far from a dead product line. No one is saying the Surface line has failed, which is shipping still about half as many units as the Mac.
Shout out to Horace Dediu with Asymco who compiled this data, what a champion.