[chrislomax]

Sorry I didn't make it clear at all!

We had 3 months where we had 20 minutes of downtime. The edge router was ~15 minutes and there was a denial of service on a machine in the same portion of the network which took a few minutes to isolate.

That is the only downtime we received in our 12 month initial contract which started Feb 2013 and ended Feb 2014 (we are on a rolling contract now).

So (20 / 12) = 1.6 minutes a month averaged. For arguments sake it puts us around the four 9s in availability a month.