fection ery : ▁ 8 1 % ▁ ▁Man - made ▁fib res : ▁ 7 9 % ▁ ▁Co al ▁extra ction : ▁ 7 9 % ▁ ▁So ft ▁drink s ▁and ▁min eral ▁waters : ▁ 7 5 % ▁ ▁P estic ides : ▁ 7 5 % ▁ ▁We ap ons ▁and ▁am mun ition : ▁ 7 7 % ▁ ▁UK ▁indust ries ▁with ▁the ▁lowest ▁five - f irm ▁concentration ▁r ati os ▁include ▁the ▁following : ▁ ▁Metal ▁for ging , ▁pressing ▁etc .: ▁ 4 % ▁ ▁Pl astic ▁products : ▁ 4 % ▁ ▁F urn iture : ▁ 5 % ▁ ▁Const ruction : ▁ 5 % ▁ ▁Struct ural ▁metal ▁products : ▁ 6 % ▁ ▁Wh oles ale ▁distributions : ▁ 6 % ▁ ▁General ▁purpose ▁mach in ery : ▁ 8 % ▁ ▁Wood ▁and ▁wood ▁products : ▁ 9 % ▁ ▁Electric ity ▁specific ▁measures ▁ ▁Standard ▁concentration ▁r ati os ▁have ▁performed ▁poor ly ▁in ▁explaining ▁marg ins ▁in ▁certain ▁mark ets , ▁especially ▁electric ity ▁mark ets , ▁where ▁supply ▁and ▁demand ▁must ▁be ▁bal anced ▁in ▁real ▁time . ▁ ▁As ▁to ▁account ▁for ▁the ▁specific ities ▁of ▁electric ity ▁mark ets ▁the ▁specific ▁struct ural ▁measures ▁such ▁as ▁the ▁P iv otal ▁Supp lier ▁Index ▁and ▁Res id ual ▁Supp lier ▁Index ▁have ▁been ▁proposed . ▁The ▁Her find ahl ▁index ▁and ▁the ▁concentration ▁r ati os ▁focus ▁on ▁the ▁market ▁shares ▁of ▁companies ,