That is certainly true -- and has probably been true for at least the past 90 years or so, but has this been true for, say, the past 500 years? As I said earlier, my understanding is that interpersonal violence in the West was was far, far more rampant in earlier centuries (e.g. people murdering each other over minor personal affronts, etc.) Then -- again, so I've heard -- since the advent of industrialization, the rate of interpersonal violence declined rapidly and has since remained relatively steady since the 1920s or so.
If this really is the long term trend, I think it raises two interesting questions, namely: 1) why did industrialization suddenly make life more precious? 2) why does everyone seem to think American culture is so much more violent today than it has been in the past?
-WD