Getting a total percentage

[lsmith48461]

I have a chart where I want to show quantity delivered on the due date is or isn't the same as the actual ship date. The Dimension is City. I have two expressions:

Order Qty =sum(OrderQuantity)

and

Order Qty On Time =If(DueDate = ShipDate, sum(OrderQuantity), 0)

Everything is fine except when I add a third column for percentage.

% Order Qty On Time =[Order Qty On Time] / [Order Qty]

The column detail naturally shows either 100% or 0%

The problem is on the Total line where nothing I have tried shows the correct percentage which should be around 85%. I've tried multiple combinations using the AGGR or TOTAL functions, but nothing seems to work.

Suggestions?

See below.