Nice to know, and nice graphs. But IMHO it is a bad idea to define ranges in a format such that the end value is included. The label "20 ≤ 30" suggests that the value 20 is included, while in fact it belongs to the range "10 ≤ 20". I realize that defining the range in Proc Format as 10 -< 20 (which I see as best practice) would remove the whole reason for trying to include the ≤ symbol in the graph, but it should be easy to think of another example.