I've coded up a webserver that gets the averages from a few different places, but I couldn't find a long term history of DVC.
Long term history of DVC: see
http://galaxies.mygamesonline.org/digitalisassets.htmlThe actual plots and pages there are kind of in reverse maybe to what you want, for example the list of what all other things cost in terms of devcoins and the graphical plot of what all other things cost in terms of devcoins, but the raw underlying data would do what you want, basically you just need to pick out the devcoin columns from the lists or plots of all the other assets.
All those tables and plots are generated from a historic collection of past "latestrates.inc" files, I don't upload that collection to the website currently though, the website just has one latestrates file at a time, uploaded to
http://galaxies.mygamesonline.org/latestrates.incThe include file is included into bash shell scripts in order to compute the value of any asset relative to any other asset.
-MarkM-