INDEX VALUE PLOT

http://www.onlamp.com/pub/a/onlamp/2005/11/17/r_for_statistics.html?page=2
An index value plot is a graph that displays the index value for each point, which is the ratio of the value to the total of all the values, instead of a concrete number. The above graph shows the S&P stocks and the changes occurred over the course of ten years.