Accumulative line graph or Lorenz curve

http://people.hofstra.edu/geotrans/eng/ch4en/meth4en/gini.html

Accumulative line graph shows the proportionality of a distribution. They elements are ordered from most important to least important, and plotted based on their percentage, then compared to the perfect equality line.

http://pubs.usgs.gov/circ/2007/1294/paper1.html