Here you go with your two axis. If you want to see the second axis, you should
- assign your first two expression both to the left axis, third (percentage) to the right
- not customize the drawing area to be enlarged so that right axis isn't shown.
In doubt when creating a chart, start from scratch by creating a new chart, don't try to fiddle around with a chart you already have customized / modified a lot.
Seems like you implicitely have a lot of other requests, like calculating your measures or filtering the data accordingly.
In the properties of your chart there is a tab labeled Axes. In this tab will be a box labeled the "Expression Axes" (similar to a Y Axis) and here you can select which Expressions you want to have on the Axes and which you don't by selecting the expression and checking or unchecking the box labeled "Hide Axis".
In the same "Axes" tab you can also specify which side of the chart you want the expression axis on in a box labeled "Position" where you can select if you want the select axis on positioned on the Left (bottom) or Right (top).
You will probably want to hide all the axes' that you don't want to show, but that should allow you to have to unrelated line's on two seperate axes.
