Percentage numbers on slider bars?
 

I've been looking around, and I can't seem to find anything solid one way or the other on this one (if there is I'll gladly be pointed the way).

Is there a mod, or is it even possible, that would add a percentage number to any slider bar that doesn't already have a number associated with it? Kind of like in recent hotkey mods, when they allowed the icon size to be changed, people started adding the actual number to go along with the slider.

I think there are some slider bars, especially in the options window (like volume?) that I would not mind having an actual number/percentage beside it to look at so I'd know exactly what level the setting is at in case I need to change it temporarily.