This chart is used to visualize the Pareto distribution and the 80/20 rule, introduced by Italian economist Vilfredo Pareto in the late 19th and early 20th centuries. Pareto charts show the ranking of data within a system and their cumulative proportion. Therefore, data must always be arranged and sorted in descending order. For example, we can consider that the reasons that account for 80% of customer complaints are our most important categories and we should focus our efforts on them.