As such it is one of the simplest possible models of computation. Nevertheless, there is an elementary cellular automaton (rule 110, defined below) which is capable of universal computation.
In 2012, there were some 3,997 distinct Android devices. This year there are a whopping 11,868. Eight versions of Android are currently in use and 37.9 percent of users are running Jelly Bean, the latest version of the mobile OS. Samsung's apparent share of the market is 47.5 percent.
Xamarin offers a solution to this problem, it's called Test Cloud. Here is a Xamarin Test Cloud devices page. As of today, it shows 1,127 Android devices and 948 iOS devices. These are the number of physical devices that are in the cloud.