The following chart is reproduced from the relevant wiki under the under the terms of the Creative Commons Attribution-ShareAlike License.
I do think it makes a fair bit of sense to categorize the Iraq and Afghanistan conflicts together here, given their overlap in justification (however well- or ill-founded) as part of a Global War on Terror.
Aggregate statistics are so bloodless that they made it easy to forget the pain and grief associated with each individual life snuffed out, and while I’m not in a good place to compensate for that here, it is worth bearing in mind. These data are offered merely to provide a sense of historical scale and perspective. Naturally, I originally meant to do this on Monday.