percentage of muscle weight in body

Does anybody know where to find out what a healthy range of muscle mass is?  Information about body fat percentage is everywhere but I haven't found a word on muscle percentage.  Most scales these days measure weight, fat, water and muscle  but what does it mean?  I know a home/bathroom scale is not super hi-tech or accurate but it can give you a good idea of where you are.  My scale tells me I weigh 139 lbs, 26% fat (YIKES, I know!) 40% water and 32% muscle.

hmm, I have been trying to find something on muscle too and cant find anything either :S

With 26% fat, 40% water and 32% muscle, you obviously wouldn't have much hair, bones, internal organs etc.