Can I open a can of worms?
I'm sure this
website hosting used to say it would give 99.9% uptime...
365 days in a year is 8760 hour per hour.
11 hours downtime / 8760 hours in a year * 100 = 0.125%
100% - 0.125% = 99.875% uptime.
hmmm... now, my maths could be wrong.....