Tens of thousands of people have died in Iraq since the US-led invasion of March 2003. But exactly how many Iraqi lives have been lost is a controversial topic, with estimates varying wildly.

More than 4,000 coalition soldiers have died, but US forces do not keep complete records of civilians killed.

Nor does the Iraqi government have a precise figure. Health ministry estimates in November 2006 ranged from 100,000 to 150,000 dead.

This contrasts with a survey of Iraqi households in the Lancet, which suggested that - by July 2006 - about 655,000 Iraqi deaths were "a consequence of the war".

A survey published in September 2007 suggested that up to 1.2m people might have died because of the conflict. UK-based polling agency Opinion Research Business extrapolated the figure by asking a random sample of 1,461 Iraqi adults.

These estimates are higher than the running total of reported civilian deaths maintained by the campaign group, Iraq Body Count.

Using two media reports as its source for each death, IBC says the civilian death toll by October 2007 was between 74,000 and 81,000. But the organisation also warns that many deaths may not have been reported.

These pages - updated monthly - give an overview of the most recent estimates.