Prices tumbled Movement.down.loss $ 1.08 or 1.31 % on Thursday to settle at $ 81.12 .

By early November , however , prices had tumbled Movement.down.loss to $ 1,603.50 a tonne -LRB- for immediate delivery -RRB- , and fell Movement.down.loss steadily as stocks rose Movement.up.gain to a record 315,600 tonnes in December .

Brent has tumbled Movement.down.loss from a high Position.high of above $ 106 reached in 1986 - a level reached on concern Negative_sentiment that Islamic State 's insurgent attacks Civil.unrest in Iraq would cut Cause.movement.down.loss its supplies .

Iraq 's supply has almost tumbled Movement.down.loss in two years to about 170,000 bpd , as an economic crisis Crisis decimated its energy industry and U.S. sanctions Embargo have now slowed Slow.weak its exports .