Excel
Click the graph to open a larger view
This is a graph from a project I am working on currently, based on data on over 2400 auto models
from the EPA. All this data is what was reported by the EPA for 2009.
Link to the source data is listed below. (Note: My calculation file got corrupted and I am in the process of redoing it, let me know if you would like to see it and I will give it higher priority).
Source file from EPA (.xlsx)