Updated: Jan 28, 2020
The following chart demonstrates an overlaying bar chart, and how it can be used in a comparative sense. This graph in particular compares the frequency of domestic and foreign cars with the same mileage per gallon. As demonstrated below, the domestic and foreign vehicles can be compared easily therefore assumptions of whether foreign of domestic cars are more frequent. This graph is simple and effective for comparing data sets with just a look.
The code below can be implemented into Stata16 to create this graph: