What does the "D" on clothing mean?

[lintholds]

So I have a bunch of clothing that have a D next to the durability percentage. It reads something like "Cloth T-shirt (normal 78% D)". I've been assuming that means deteriorating and have been selling the stuff, but I didn't think things deteriorated until below 50%? Can anyone provide clarification on what the D means? I googled, but can't seem to find an answer.

[ProvoGo]

It was worn by a dead person and will give a mood penalty if your colonists wear it :)

[lintholds]

omg... so simple. thanks

[Knight9910]

Also, deterioration occurs all the way from 100% to 0%. Deterioration is just the process of it losing durability. 50% is simply the point where it becomes "tattered" and starts applying a mood penalty to the wearer.