Do not understand what toggle % truly means in Quartus PowerPlay Power Analyzer

As far as I've understood things it a fairly simple estimate of the % of your registers that will toggle on each clock edge.

Ie in a module that has 1000 registers and a toggle % of 23.5% then 235 registers change state every clock cycle.

I usually wind it up for safety but haven't had many power/temperature critical designs so am normally just checking my power supplies are up to the job.

Nial.