Max CPU can spike to 99 or 100% utilization in normal usage occasionally, but if it happens often, it is probably indicative of a problem.
Average CPU for the 4500 series switches ranges from 20-40% or higher even when completely idle. Depending on the features enabled and type and amount of traffic going through the switch, your average range could be anywhere.
Here's a good doc on understanding CPU utilization on the 4500 series switches:
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...