Violent Crime at a 42-year low

Last week, the FBI released its national crime report for 2012.
By a slight margin, the nation’s violent crime rate decreased in 2012–relative to 2011–making it the lowest it has been since 1970.

Read more: http://www.ammoland.com/2013/10/not-a-peep-from-obama-violent-crime-reaches-42-year-low/#ixzz2gbo4QB4x

 
Violent Crime at a 42-year low, but gun onership by private citizens is at an all time high.   How can this be?