Is visibility discrete or continuous?

On the inventory screen, there is a bar showing how visible you are with your current loadout. Is the visibility value discrete (ie. there are only three possibilities; low, medium, and high) or continuous (ie. the bar being at the high end of the medium range is more visible than the bar being at the low end of the medium range)?

To phrase the question another way (in case it's not clear), if we think of low, medium, and high visibility as having values of 1, 2, and 3, is there any difference in visibility between 2.1 and 2.9?

Solution 1:

Visibility is discrete. If your bar is at the first third, your visibility is low. It's medium on the second third and high on the last third. (Might still apply for consoles!)

In Update #13 visibility meter was replaced with a detection risk number, which is a number below or equal to 75, and it directly shows you the risk of being detected. The higher the number, the easier you will be detected.