A team of American and Iraqi public health researchers has estimated that 600,000 civilians have died in violence across Iraq since the 2003 American invasion, the highest estimate ever for the toll of the war. This from the New York Times:

This is the second study by researchers from the Johns Hopkins
Bloomberg School of Public Health. It uses samples of casualties from
Iraqi households to extrapolate an overall figure of 601,027 Iraqis
dead from violence between March 2003 and July 2006.

The
findings of the previous study, published in The Lancet, a British
medical journal, in 2004, had been criticized as high, in part because
of its relatively narrow sampling of about 1,000 families, and because
it carried a large margin of error.

The new study is more
representative, its researchers said, and the sampling is broader: it
surveyed 1,849 Iraqi families in 47 different neighborhoods across
Iraq. The selection of geographical areas in 18 regions across Iraq was
based on population size, not on the level of violence, they said.