Iraq's oil ministry said rebels inflicted a total of 186 attacks in 2005 on various oil installations, making a huge economic dent at a time when the country's security fibre was simultaneously torn threadbare.
"Iraq lost oil revenues worth $US6.25 billion ($A8.47 billion) in 2005 due to sabotage on the country's oil infrastructure," Assem Jihad, spokesman for Iraq's oil ministry said.
He said insurgents carried out 186 attacks on the country's oil installations last year, killing 47 oil engineers and technicians and another 91 police and security guards.
Mr Jihad said most of the attacks were concentrated on the northern oil installations which transport oil to the Turkish port of Ceyhan.
He said the loss includes $US3.12 billion ($A4.23 billion) lost from attacks on the domestic pipelines transporting oil and gas and $US2.71 billion ($A3.67 billion) from attacks on exporting pipelines.
About $US400 million ($A541.79 million) were lost from explosions at its crude oil wells and another $US12 million ($A16.25 million) from attacks on pipelines between the wells and refineries.
The country's oil infrastructure remains a favourite rebel target, apart from the security forces, as even in 2004 the loss from oil revenue due to such attacks was seven billion dollars.
And since the fall of the regime of former president Saddam Hussein these losses have touched $US20 billion ($A27.09 billion).
Former Iraqi Oil Minister Thamer Ghadban in January 2005 had termed the country's raging insurgency as "war on Iraq's oil infrastructure".
Mr Jihad said that during 2005, the average crude oil production was at 1.5 million barrels per day.