Core Plot advice - Best way to make a pie-like bar chart? (% of total)

So I'm trying to create a bar chart similar to this:
_{(source: instantshift.com)}

Is there a nice way to do this in CorePlot? If not, should I just plot two bar plots? One of the data values and another with 100%? and try put them on top of each other?

Use two bar plots. Give one a base value of zero (0) and the other a base value of 100. Give them both the same tip value for the same index. That way they don't overlap but the ends of the bars butt up against each other.