Year Percent 1995 17.22 1996 17.22 1997 15.07 1998 15.74 1999 15.74 2000 16.73 2001 16.73 2002 16.36 2003 16.36 2004 18.33 2005 18.33 2006 16.18 2007 16.17 2008 16.98 2009 17.83 2010 16.39 2011 15.19 2013 14.42 2014 13.58 2015 12.92 2016 14.98