http://developer.android.com/about/dashboards/index.html
Heck, Gingerbread is at 6% versus 10% for Lollipop cumulative. And 5.0 has 9 times the adoption of 5.1. Instead of announcing a new Android version, why not announce how you're going to get new versions of Android onto devices already in wild? And if Google wants to blame the OEMs for this, the OEM you owned when I got my Motorola X (and still owned when you shipped 5.0!) still hasn't been updated. It's absurd.