Naive question here, but how much of the time would you expect cpus in a data center to idle? Also, you save 20% of idle (which is a sizable percentage, but not

Naive question here, but how much of the time would you expect cpus in a data center to idle? Also, you save 20% of idle (which is a sizable percentage, but not much in absolute wattage) and nothing when not idle (which is much higher wattage). So how much do you save per month overall?1%, 0.1%?