In contrast , in the control group , 226 ( 34.3 % ) segments were grade 0 ; 173 ( 26.3 % ) , grade 1 ; 175 ( 26.6 % ) , grade 2 ; 45 ( 6.8 % ) , grade 3 ; 23 ( 3.5 % ) , grade 4 ; and 17 ( 2.6 % ) , grade 5 .