Sample scenario: Let's say in each year, I have this many cats:
2010: 6
2011: 8
2012: 20

Out of those cats, let's say that the following number have been neutered:
2010: 1
2011: 4
2012: 18

Is there a way for me to create a form of bar chart that shows the total
number of cats per year as a "background" bar, with the total number of
neutered cats in each year as a skinnier "foreground" bar that is a different
color and overlays the background bar?