Here are Android OS version revolutions:
Android 1.0 (API level 1 – September 2008)
Android 1.1 (API level 2 – February 2009)
Android 1.5 Cupcake (API level 3 – April 2009)
Android 1.6 Donut (API level 4 – September 2009)
Android 2.0 Eclair (API level 5 – October 2009 – May 2010)
Android 2.2 Froyo (API level 8 – May 2010 – November 2011)
Android 2.3 Gingerbread (API level 9 – December 2010 – September 2011)
Android 3.0 Honeycomb (API level 11 – February 2011 – February 2012)
Android 4.0 Ice Cream Sandwich (API level 14 – October 2011 -March 2012)
Android 4.1 Jelly Bean (API level 16 – July 2012 – October 2012)
Android 4.2 Jelly Bean (API level 17 – November 2012 – February 2013)
What’s next?
Android 4.3 (Jelly Bean) or 5.0 (Key Lime Pie)?