Year Percent 1994 5.17 1995 5.32 1996 5.45 1997 4.88 1998 4.37 1999 4.32 2000 4.12 2001 3.89 2002 3.76 2003 3.17 2004 1.62 2005 1.87 2006 1.99 2007 2.84 2008 2.66 2009 2.57 2010 2.42 2011 2.18 2012 2.06 2013 1.97 2014 2.06 2015 1.73 2016 1.64 2017 1.67