december 27 , 2008 , december 29 , 2007 , and december 30 , 2006 , respectively . in the next five years , the amortization expense is estimated to be $ 22859 , $ 22285 , $ 20408 , $ 10465 , and $ 3965 , respectively . marketable securities management determines the appropriate classification of marketable securities at the time of purchase and reevaluates such designation as of each balance sheet date . all of the company 2019s marketable securities are considered available-for-sale at december 27 , 2008