I don't really know...
But even ever I see 100% uptime, its blacklist for me :P
No one and I will say again NO one can give you that.
Even if he does a Loadbalancer act with 10,000 w UPS units and with 10 servers mapping each other and with DNS fail over plus immediate kick in routers when one fail.
There is still a slight possibility if failure because things are unpredictable. Nothing is 100%
