Accumulated Line Graph or Lorenz Curve

http://www.unc.edu/depts/econ/byrns_web/Economicae/Figures/Lorenz.htm
An accumulative line graph, otherwise known as a Lorenz curve, is a graph that depicts a degree of inequality between two distributions. The value that is measured to find the level of inequality is the slope.  The Lorenz Curve combines the data from both categories so it is a good and accurate measurement of determining whether or not the graph is increasing or decreasing.