translation.en: This is from the FBI Uniform Crime Statistics. You can see that there is a fairly low rate of violence in the '50s and the '60s, then it soared upward for several decades, and began a precipitous decline, starting in the 1990s, so that it went back to the level that was last enjoyed in 1960.
translation.zh: 这是联邦调查局犯罪统计数据。从中可知 在50至60年代暴力行为发生率相对较低 经历几十年的上升 在90年代开始骤降 直至回到60年代的水平