A Pareto chart is a type of chart that contains both bars and a line graph. It is named after Vilfredo Pareto, an Italian economist who observed that 80% of the land in Italy was owned by 20% of the population. The purpose of the Pareto chart is to highlight the most important among a set of factors, such as the most common sources of defects, the highest occurring type of defect, or the most frequent reasons for customer complaints. The chart is a combination of a bar graph and a line graph, where individual values are represented in descending order by bars, and the cumulative total is represented by the line. The bars are presented in descending order, from tallest to shortest, so that it is easy to see which factors are most significant. The line represents the cumulative percentage of the factors. Pareto charts are useful in quality control to find the defects to prioritize in order to observe the greatest overall improvement. They can be generated by simple spreadsheet programs, specialized statistical software tools, and online quality charts generators. Pareto charts are one of the seven basic tools of quality control.