2014
2013
Note: Data were not available to update the D6 factor in October and November 2013 due to the federal government shutdown.
June2012
2011
2010
2009
2008
2014
2013
Note: Data were not available to update the D6 factor in October and November 2013 due to the federal government shutdown.
June2012
2011
2010
2009
2008