Click on one of the series in the chart, you will see the series formula in
the formula bar at the top of the screen. It will look something like this;
=SERIES("Series name",Sheet1!$A$1:$A$3,Sheet1!$B$1:$B$3,1)

Then click on the formula in the formula bar, and press F9. The series
formula will now show values. Like this;
=SERIES("Series name",{1,2,3},{4,5,6},1)

Select the whole formula (or just the bits between curly brackets) and copy
it to a worksheet cell. Use Data - Text to Columns to parse the values into
something you can use.

Ed Ferrero
www.edferrero.com