Column Chart and Comparing Average Completion Time Values

[gosoccer]

Hi guys, :)
I have a requirement to show three Columns in a chart.

Column 1: Deal was contacted
Columns 2: Dealer Sold the Car
Column 3: Dealer Delivered the Car

As you can see in the attachment, that is not that hard and I have the three columns done.

But now, I have to add a Trent line that would show these columns based on the Entire United States Averge
for the same processes shown above (Deal was contacted,Dealer Sold the Car,Dealer Delivered the Car)

SO, my question is how to create the Trent line to show a Comparison between the entire US and the specific State.
Please see attached.

Thank you in advance for your time.