For HPV 16 or 18 , the absolute risk for detection of CIN 2 or worse on random biopsy in the overall population was 13.1 % ( 40/305 , 95 % CI 9.8-17 .4 % ) and 8.2 % ( 25/305 , 95 % CI 5.6-11 .8 % ) for CIN 3 or worse .