Technically, %Complete refers to elapsed time; %WorkComplete refers to the ActualWork divided by the Total Work.
If -- and ONLY if -- you are accurately tracking work on every task then
View > Tracking Gantt
Format > Bar styles
In the top half of the Bar Styles popup dialog, scroll down to a blank row
Name: MyProgress
Appearance: use the bottom half of the popup dialog on the Bars tab to describe the shape. pattern and colour
Show for: Project Summary
Row: 1
From: Start
To: CompleteThrough