Note: By default, charts in Design Mode display three columns and
three rows of sample data. If your chart will have a legend and you want to
change the format of the items in the legend, specify the same number of data
rows of sample data as there will be legend items.
Note: Also, if you want to specify the number of categories
displayed on the Category axis of a chart, specify the same number of
categories of sample data as there are actual categories.