Percentage Base
Depending on the chart type, the following options are available for the base (denominator) used in percentage calculations. Specifying the percentage base is not available for cumulative percentages. The base for cumulative percentages is always the grand total because a different percentage base could conflict with the cumulative percentage.
Grand Total. Percentages are based on the total number of cases or responses in the chart. Adding up all of the graphic elements across all panels in the chart equals 100%.
Total for Each Axis Category. Percentages are based on the total number of cases or responses in a particular axis category. Adding up the graphic elements in the category equals 100%. This is the percentage base that you would select so that each stack or each cluster adds up to 100%.
Total for Each Legend Variable Category. Percentages are based on the total number of cases or responses with the same color, pattern, or other aesthetic. Adding up the graphic elements with the same aesthetic equals 100%. For example, adding up all of the green bars in the chart would equal 100%.
Total for Each Panel. Percentages are based on the total number of cases or responses in the same panel. Adding up the graphic elements in each panel equals 100%.