The pie chart was originally developed as a simple graphic representation of proportions of elements in a set of figures. The pie chart is an easy to read graph, more efficient than bar graphs and using less space in statistical formats where there's a lot of information. It's common to see pie graphs used in corporate and government reports and statistics, used as representations of proportionate demographics, expenditure, etc. Pie charts are usually done in colored sections to differentiate the elements in the set. When done as a series of charts, pie charts work well for comparing data, and trends.