Google Dashboard lays out the current distribution of Android versions. Android 6.0 Marshmallow is gaining ground while Lollipop, KitKat, Jelly Bean, Ice Cream Sandwich, and Gingerbread have all fallen month-over-month.
http://www.notebookcheck.net/Google-Android-6-0-Marshmallow-now-on-13-3-percent-of-active-Android-devices.169608.0.html