Minimum Android Version Support?

Hello Community,

I apologize if this is in an obvious location on the site/forums. I did a search, but did not find anything. I'm looking for for the minimum version to target for Android phones in using Xamarin.Forms. That is, what is the minimum version of Android that I can consider using for a Xamarin.Forms solution.

I am calculating some market analytics and am looking to guestimate the amount of Droid marketshare. For reference, here is what I am using:
http://www.netmarketshare.com/report.aspx?qprid=10&qptimeframe=M&qpsp=189&qpch=350&qpmr=24&qpdt=1&qpct=3&qpcustomd=1&qpcid=fw98607&qpf=1

Thank you for any assistance you can lend!
Michael