Stacked Column Charts show how the components contributing to the total vary over time. For example, the chart below shows how the yearly sales of three products add up to the total sales of the company.
One drawback of Stacked Column Charts is that since only one segment of the components is measured against a common baseline, it becomes difficult to compare how all the other floating segments change over time.
The reason why the chart below works as a stacked Column Chart is because the primary purpose of the chart is to compare the sales of Product C versus the sum of sales of Product A and B. And since the sum of sales of products A and B is relatively stable over time, it formed a common base line for Product C sales.
Adding labels to show sales by product is very easy to do in Excel. However, adding labels to show total sales requires some additional effort.