As the name implies, the 100% stacked bar or column chart uses the percent unit for the y-axis. As a result, if you are comparing across multiple groups/bars, each would have the same height taking up the full range of the value axis. The chart is typically used when the author wants to highlight the portion of the total that each segment in a bar comprises. The chart is especially useful when comparing across groups of different sizes or along a timeline. In the example below, we use the 100% stacked bar chart to examine educational attainment in specific US geographies.
Relative to the rest of the US, a higher portion of Silicon Valley and San Francisco residents have a Bachelor, Graduate or Professional degree. The 100% stacked column helps the reader quickly arrive to this conclusion. If we had used a regular stacked chart the American population would have dwarfed Silicon Valley and San Francisco making the key message difficult to obtain. Still the sum displayed on top of each column gives insights into the absolute numbers behind the percentages in the 100% chart.
The 100% stacked bar chart is a standard Aploris offering. With Aploris, the user can switch between regular and 100% stacked bars with the just a few clicks allowing them to quickly test which graph best communicates the intended insight. In addition, Aploris labels can be automatically adjusted to show the absolute value, the percent of the total, or both.