I thought this would be easy, but I cannot figure out how to use conditional
formatting with iconsets the way I want.

If I am comparing results from one month to the next I want to show a green
light or arrow if the current month's sales were higher than last month, a
yellow light if it was the same and a red light if it declined.

Month 1 Month 2

50 60 - green
55 55- yellow
60 50 - red

This seems pretty basic, am I missing something simple?