If you are on a dual processor your average should be ~20 to 25% cpu.
But here are some previous post to help decrease cpu usuage.

To keep your stake,
In coin control , every few days or weekly, look at the blocks , click on confirmations, this will sort the blocks, select some of the ones with the lowest confirmations, and send them to your default receive address (You will have to copy & paste your default receive address into send field, no way to add it your send address book Yet.) By selecting the lowest confirmations you only combine coins that have staked recently and they won't lose more than a few days from their maturity.

Or if CPU is more important than POS Stake , then combine them immediately.
Lower the # of Blocks , less CPU it uses.

Below is a post that confirms it works.
Follow up to using coin control to reduce the amount of blocks and reducing cpu use.  It works!
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2 weeks ago I had over 8000 blocks and my cpu was at 19.3%
I started combining blocks with the goal of getting down to 100.  There was no noticeable change in cpu until I got down to 900 blocks, this takes time if you want to preserve your coin age and I figure I will be down to about 80 blocks in 2 more weeks.

Currently sitting at 140 blocks and cpu use is at 5%, which is a big improvement - thanks for the tips!

Anyone who has high cpu use with the wallet might want to use the coin control and start consolidating the blocks into a smaller number, it's definitely made an improvement for me.
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Only other factor would be if you are running it in a VM.