It would be the equivalent of around 66.66666(etc) 9/11s by percentage.

Iraq has approximately 30 million people, not 30,000. The US has almost 300 million. Approximate numbers of Iraqi civilians killed by US and "coalition" forces in the invasion and occupation probably more than 20,000 (conservative figure).

20,000 x 10 = 200,000... divided by 3,000 = 66.66666(etc.)

It's still a sobering thought.