September 2006 futures represented 30% of total trading volume, March 2006 futures represented 25% of total trading volume, while September, October, November, December, February 2006 and June 2006 accounted for 1%, 7%, 8%, 9%,2% and 18% respectively.
On September 30, 2005 the open interest among October – December 2005, February 2006, March 2006, June 2006 and September 2006 contracts was distributed as follows: 16%, 13%, 9%, 2%, 22%, 15%, 23%.