A DOJ Bureau of Justice Statistics (BJS) "special report"  shows that "firearm-related" homicides fell by 39 percent between 1993 and 2011

It also showed that violent crime--or "nonfatal firearm-related violent victimization against persons aged 12 or older"--declined by 70% over the same time period.
The BJS report was released in May 2013, but was under-reported amid the push for new gun control laws. The information in it is detrimental to many of the gun control arguments which were being propounded at the time.
For instance, while Democrats in various parts of the country were pushing legislation to end the "gun show loophole," the BJS report showed that "among state prison inmates who possessed a gun at the time of [their] offense, less than 2 percent bought their gun at a flea market or gun show."
And a subsection of the report focused on 1997 to 2004 showed that only two percent of state inmates and three percent of federal inmates used "a military-style semiautomatic or fully automatic" in the commission of their crime. 
The success of the gun control lobby was evidenced by an LA Times column which ran at the same time as the BJS report. According to the Times, although "gun crime...plunged in the United States since its peak in the middle of the 1990s...few Americans are aware of the dramatic drop, and more than half believe gun crime has risen."