Because that's how Petreaus is spinning that sectarian murders are way down...
http://www.cnn.com/2007/POLITICS/09/10/patraeus.transcript/index.html?section=cnn_latest<snip>
Civilian deaths of all categories, less natural causes, have also declined considerably, by over 45 percent Iraq-wide since the height of the sectarian violence in December. This is shown by the top line on this chart. And the decline by some 70 percent in Baghdad is shown by the bottom line.
Periodic mass casualty attacks by al Qaeda have tragically added to the numbers outside Baghdad in particular. Even without the sensational attacks, however, the level of civilian deaths is clearly still too high and continues to be of serious concern.
As the next chart shows, the number of ethno-sectarian deaths, an important subset of the overall civilian casualty figures, has also declined significantly since the height of the sectarian violence in December. Iraq-wide, as shown by the top line on this chart, the number of ethno-sectarian deaths has come down by over 55 percent, and it would have come down much further were it not for the casualties inflicted by barbaric al Qaeda bombings attempting to reignite sectarian violence.
In Baghdad, as the bottom line shows, the number of ethno- sectarian deaths has come down by some 80 percent since December.
This chart also displays the density of sectarian incidents in various Baghdad neighborhoods, and it both reflects the progress made in reducing ethno-sectarian violence in the Iraqi capital, and identifies the areas that remain the most challenging.