This image was uploaded in the JPEG format even though it consists of non-photographic data . This information could be stored more efficiently or accurately in the PNG or SVG format. If possible, please upload a PNG or SVG version of this image without compression artifacts , derived from a non-JPEG source (or with existing artifacts removed ). After doing so, please tag the JPEG version with {{Superseded|NewImage.ext}} and remove this tag. This tag should not be applied to photographs or scans. If this image is a diagram or other image suitable for vectorisation , please tag this image with {{Convert to SVG}} instead of {{BadJPEG}} . If not suitable for vectorisation, use {{Convert to PNG}} . For more information, see {{BadJPEG}} .

Summary

The graph was created by Robert Vienneau and is used with his permission. He explicitly gives the permission in the comments of his blog here: https://www.blogger.com/comment.g?blogID=26706564&postID=8884880137111486330

Licensing

I, the copyright holder of this work, release this work into the public domain . This applies worldwide. In some countries this may not be legally possible; if so: I grant anyone the right to use this work for any purpose , without any conditions, unless such conditions are required by law.