http://www.cbot.com/cbot/www/page/0,1398,21+70,00.html
http://www.cbot.com/cbot/quotes/estimated_volume/0,2517,12+410+296,00.html
http://www.cme.com/prices/bulletinindex.cfm
(choose monthly volume reports at the bottom)
The truth is, and I was looking at this earlier today, for most of...