Year Percent 1993 0.46536 1994 2.50048 1995 2.82851 1996 3.28758 1997 4.12467 1998 3.355 1999 2.98217 2000 3.63615 2001 2.864 2002 2.7749 2003 2.84839 2004 2.59712 2005 2.79249 2006 2.66924 2007 2.75394 2008 2.55755 2009 2.84032 2010 2.74203 2011 2.25832 2012 2.35344 2013 2.39292 2014 3.02114 2015 3.97326 2016 3.67198 2017 3.41297