Year Percent 1991 4.20778 1992 3.81967 1993 5.85685 1994 2.65077 1995 10.34956 1996 7.04876 1997 8.78576 1998 6.85456 1999 6.72696 2000 5.80781 2001 7.54129 2002 5.38038 2003 4.87257 2004 4.36076 2005 7.52452 2006 16.20078 2007 50.50475 2008 47.47706 2009 -2.27204 2010 -15.98922 2011 7.46273 2012 8.30531 2013 -2.78971 2014 9.19677 2015 -4.00314 2016 55.48993 2017 -8.91136