0 % ▁to ▁ 4 0 %. ▁This ▁category ▁ranges ▁from ▁perfect ▁competition ▁to ▁an ▁o lig opol y . ▁Med ium ▁concentration ▁ 4 0 % ▁to ▁ 7 0 %. ▁An ▁industry ▁in ▁this ▁range ▁is ▁likely ▁an ▁o lig opol y . ▁High ▁concentration ▁ 7 0 % ▁to ▁ 1 0 0 %. ▁This ▁category ▁ranges ▁from ▁an ▁o lig opol y ▁to ▁mon opol y . ▁Total ▁concentration 1 0 0 % ▁means ▁there ▁is ▁a ▁mon opol y . ▁ ▁Problem s ▁ ▁The ▁definition ▁of ▁the ▁concentration ▁ratio ▁does ▁not ▁use ▁the ▁market ▁shares ▁of ▁all ▁the ▁fir ms ▁in ▁the ▁industry ▁and ▁does ▁not ▁provide ▁the ▁distribution ▁of ▁firm ▁size . ▁It ▁also ▁does ▁not ▁provide ▁a ▁lot ▁of ▁detail ▁about ▁compet it iveness ▁of ▁the ▁industry . ▁The ▁concentration ▁r ati os ▁just ▁provide ▁a ▁sign ▁of ▁the ▁o lig opol istic ▁nature ▁of ▁an ▁industry ▁and ▁indicate ▁the ▁degree ▁of ▁competition . ▁The ▁Her find ahl ▁index ▁provides ▁a ▁more ▁complete ▁picture ▁of ▁industry ▁concentration ▁than ▁does ▁the ▁concentration ▁ratio . ▁ ▁Con cent r ation ▁r ati os ▁in ▁United ▁Kingdom ▁▁ ▁UK ▁indust ries ▁with ▁the ▁highest ▁five - f irm ▁concentration ▁r ati os ▁( CR 5 ) ▁include ▁the ▁following : ▁ ▁Sug ar : ▁ 9 9 % ▁ ▁Tob acco ▁products : ▁ 9 9 % ▁ ▁Gas ▁distribution : ▁ 8 2 % ▁ ▁O ils ▁and ▁f ats : ▁ 8 8 % ▁ ▁Con