Android Oreo was available to Pixel and Nexus devices. Other Manufactures are yet to roll out Oreo update to their flagship smartphones. Now the mobiles that runs with Oreo Os shows up in the list and it measured at 0.2%, this will grow quickly when the manufactures start pushing Oreo to their smartphones.
7.0 Nougat grew 2 percentage points while 6.0 Marshmallow remained same. Lollipop, KitKat and all the other older versions are shrinking slowly.