Coeff. 0 items that are not randomly dropped at a level. They appear under certain conditions (for example you have hidden



Coeff. 6 are the rarest items, coeff. 1 the most common. In numbers it is approximately:
coeff. 1: 52.323% - about 1 in 2 items
coeff. 2: 34.085% - about 1 in 3 items
coeff. 3: 11.999% - about 1 in 8 items
coeff. 4: 01.542% - about 1 in 65 items
coeff. 5: 0.1400% - about 1 in 700 items
coeff. 6: 0.0045% - about 1 in 22,000 items
These numbers are only chances, not predictions!
This is from MT site.