Showing Millions on one Axis, Percentages on the Other with Clustered Column Chart

I'm not quite sure what you are looking for, but what I did here was to plot the two series. I selected the axis and temporarily adjusted the maximum to 1. This allowed me to see the contribution series. I selected the series and put it on the secondary axis. I then reset the original axis to automatic. The I played with the series overlap and gap width so the columns would not eclipse each other.