Add a second XY series similar to below (this example shows a chart length
of 100 - yours needs to match your specs.). Remove the line markers and
adjust increase the line weight. Color the line black or whatever to match
the rest of your chart.
If you have a y-axis and it is set at the default of x=0, double-click
it and from the Patterns tab adjust the format of the line as desired
(I'd start by picking a thicker line than the default).
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Regards,
Tushar Mehta www.tushar-mehta.com
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