Calculate column totals from percentage or other units

[cg-sla]

We'd like to be able to have the column totals (in Green) calculate the percentage of cards in each column. For example, if I have 5 cards, and there are 2 in the first column and 3 in the second column, the green total values should be 40% and 60%. I can accomplish a workaround by using formula fields, but it doesn't display the (%) unit.