May 2006 futures represented 32% of total trading volume, while April 2006, June 2006 - December 2006 accounted for 22%, 21%, 10%, 5%, 6%, 1% and 3% respectively.
On April 30, 2006 the open interest among May 2006 - December 2006 and March 2007 contracts was distributed as follows: 39%, 16%, 6%, 6%, 22%, 2%, 8%, 1%.