. in the first two quarters of 2006 , margins were favorable compared with the prior year as average sales prices outpaced containerboard cost increases , but average margins began to decline in the third quarter as containerboard increases outpaced the increase in box prices . operating profits in 2006 decreased 72% ( 72 % ) from 2005 and 86% ( 86 % ) from 2004 levels , primarily due to higher distribution , utility and raw material costs , and inventory adjustment charges