Thanks to W7EJ, I have been able to extend the historical database of cleaned and augmented CQ WW data back one further year, to 2007. As far as I can tell, there is no source anywhere for CQ WW logs prior to 2007.
The new cleaned data are in a single compressed (xz) file downloadable from:
https://www.copy.com/s/t%3AjLcUe4NDu7BvPcfC%3Bp%3A%252Fpublic-logs/cq-ww/cq-ww-2007--2014-clean.xz%3Boid%3A148
The MD5 checksum of this file is:
1d96c696ae20a87f4de7a66e2a523519
Similarly, the augmented data are downloadable from:
https://www.copy.com/s/t%3AjLcUe4NDu7BvPcfC%3Bp%3A%252Fpublic-logs/cq-ww/cq-ww-2007--2014-augmented.xz%3Boid%3A149
The MD5 checksum of this file is:
a7674758f3a7c2878944be9f1b6dfd81
