I'm curious how they determined who were civilians.
I'm not actually disputing the numbers, as I personally don't have any additional facts on the subject. However, when I looked at that wiki page, I didn't see anything that addressed how the civilians killed were actually classified as civilians. Did their family members say that they weren't insurgents? Obviously that data could be skewed as many people may not want to admit that a relative was an insurgent. Hell, they may not even know for that matter. Perhaps it was based simply on whether weapons were found near the bodies, that sounds pretty logical, but it has its faults as well.
It wouldn't surprise me to find that the numbers were actually much higher or much lower, as I can only imagine it to be a very difficult thing to determine.