So, I've got some data that I'd like to plot on an X-Y scatter graph. Unfortunately, X and Y are the wrong way round in the spreadsheet, so that when I plot the graph, Excel puts my Y values along the X axis and my X values up the Y axis.

Double unfortunately, I can't swap the columns in the source data -- the file's generated as CSV by another application.

How do I persuade Excel to plot the axes the other way round?