I can't seem to respond directly to your question, so I hope that you see this. You can eliminate the risers by placing spaces between every second data point. It is all about laying out your data. I cannot find this data set, but here is a sample of how to arrange the data:
X Var Y Var
Everything else is the same. Make sure that you select the entire range (including blanks) when creating the chart.
You can also do it with formatting in the chart. Click the point at the top of a riser twice (not a double click) to select it. Then, format the data point and set it to No Line. Do this for each riser. I think it is much easier to set up your data appropriately.