What is the the loss percentage of devices, when building only for ARM-based

Am close to publish an app using ionic for sure the problem is the size of the app since i used Crosswalk. i made quick search and found the majority of Android phones use ARM-based cpu. publishing for only ARM architecture will save me around 20MB and opinions about this

According to Google Play, my x86 build supports 255 devices whereas my ARM build supports 7973 devices.

thank you, does it also tell you how many users with x86 devices have downloaded your app ?