Back in October of 2015 Google started shipping the Nexus 5X and Nexus 6P, but it's clear from the poor adoption rate for Android 6.0 Marshmallow that these handsets aren't exactly flying off the shelves.
Google's official usage figures for Android for the 7-day period ending January 4, 2016 put Android 6.0 Marshmallow usage at a mere 0.7 percent. Put that another way, more than four times as many devices are running Gingerbread, a platform that hasn't seen an update in over four years.
And it's clear that the new Nexus handsets haven't been a big hit over the holidays because usage figure for Marshmallow have only climbed by 0.2 percentage points since early December.
Android 5.0/5/1 Lollipop did see adoption grow over the same period, increasing by 3.2 percentage points. All other versions either saw a decline or are flatlined. It's likely that over the coming months Lollipop will overtake KitKat to be the most prolific platform.