They have dropped considerably since broken windows policing and three strikes sentencing became the norm, as this article from Daily Signal notes.
From 2000 to 2012, the U.S. violent crime rate fell over 23 percent. Such an improvement in the social fabric would be cause enough for celebration. But the crime drop of the 2000s followed an even larger decline in the previous decade: 32 percent from 1993 to 2000. The 1990s crime drop (in both personal and property crime) was so sharp and so unexpected that by 2000, most criminologists were predicting that an uptick was all but inevitable. Instead, after a brief pause, the crime fall again picked up steam, extending the longest and steepest crime decrease since World War Two.
America’s two-decades-long victory over crime reversed what had seemed to be an inexorable increase in lawlessness since the 1960s. The murder rate had more than doubled from 1964 to 1974, spiking again in the late 1980s and early 1990s. But just as crime was peaking in 1993, it reversed and went into freefall. The greatest beneficiaries of that crime drop have been the residents of minority neighborhoods, where crime was (and still is) highest and where the bulk of the recent crime decrease occurred.
The fact that the American crime drop encompassed every category of serious violent and property offense makes this transformation virtually unique among Western countries. Particular crimes went down by sometimes comparable amounts in other G7 countries, but those nations experienced increases in other serious offenses. And the fact that crime went down everywhere across America makes the phenomenon particularly puzzling, since crime is a local condition.
Neither liberal nor conservative root-cause theories of law-breaking have fared well over the past two decades. Even though the crime explosion during the booming 1960s should have discredited the liberal belief that economic hardship causes crime, criminologists opined in 2008 that the recession would trigger a crime increase. Instead, the recession accelerated the 2000s crime drop.
Family breakdown also moved in the opposite direction as crime, confounding conservative theories. The black unwed birth rate rose from 66.7 percent in 1990 to 71.6 percent today, and the rate among whites rose from 16.9 percent in 1990 to 29.3 percent today. Meanwhile, crime, especially that committed by blacks, plummeted.
Retrieved October 29, 2014 from http://dailysignal.com/2014/10/28/violent-crime-us-declined-rapidly-happened/