The following figure illustrates the relationship between temperature and the percentage of clouds which contain ALL water (left side axis) OR some portion of ICE (right side axis).
There are two sets of two black line curves labelled "water curves" and "ice curves". When using the figure for ALL water supercooled (<0C) clouds, use the water curves and the left axis. When trying to find the temperature versus percentage of clouds with ice, use the ice curves and the right side axis.
There are two "water curves" and two "ice curves" each because the author of the figure used two studies in each of the categories and plotted both datasets. I suggest just using the middle area between the set (either water or ice).
For example, follow the blue line up from -8C. If you are interested in finding out the percentage of clouds with ALL supercooled liquid water drops, follow it up to the interesection of the water curves and read the left side axis. Here, it is about 60% of clouds contain ALL water at -8C.
If trying to find out what percentage of clouds contain SOME portion of ice at -8C, move up from the bottom margin at -8C to the intersection of the ICE curves. Then, follow this point straight over to the right margin. Here, about 40% of clouds have SOME type of ice in them.