The rightmost graph is public domain. The leftmost is not. For all practical purposes, they are identical. The license of the leftmost graph is also not compatible with the text. The graph requires it to be used for non-commercial purposes, but the text can be used for commercial purposes. Therefore, if someone wanted to sell this (dunno why), they would have to strip out the most important image in the article. Also, I'm not sure what DF has done to the graph to claim some sort of copyright on it, but that's neither here nor there. Further, the rightmost graph presents more information without adding clutter. The fact that it's been used before is not an argument to keep it. It is inferior to the rightmost graph. -