Year Percent 1991 0.96831 1993 3.72299 1995 3.23309 1996 3.36494 1997 3.17922 1998 2.23414 1999 2.00057 2000 2.12594 2001 1.83058 2002 1.63744 2003 1.58231 2004 1.75891 2005 1.55616 2006 1.42619 2007 1.17979 2008 0.91012 2009 0.978 2010 1.1471 2011 0.97774 2012 0.99815 2013 1.06447 2014 1.21424 2015 1.45862 2016 1.44722 2017 1.31876