setting sag

I've noticed that the amount of sag that should be set is often expressed as percentage of total travel.  This, it would seem, that I know the length of travel for the rear shock.  I don't.  Where can I find it for a (stock) 2018wr? Or if I knew the (sag) distance in inches or MM that would help too.  I weigh 180lbs.

thanks!

Rear wheel travel is 10.6 inches according to Yamaha's own specifications.
The rule of thumb is you want your sag to be one-third of wheel travel.
That would be 3.5 inches.

Yes, static sag 10%, racesag (when you sit on it) 30%