I have a set of data in a chart that on one axis shows percentage data and
the other axis the absoulte values, such as:
Primary Secondary
Period1 5% 100
Period2 -5% -20

How do I fix the axis so the 0 point is the same on both axis (without
manually working it out). This is a chart I want to copy for other data so
would be good to automate it now.

Thanks