Year Percent 1990 -10.03791 1991 -2.97173 1992 0.9928 1993 -7.94408 1994 -10.21522 1995 -9.75689 1996 -10.33675 1997 -13.53763 1998 -14.87896 1999 -9.98197 2000 -14.26647 2001 -13.08079 2002 -18.9314 2003 -15.75659 2004 -19.4618 2005 -16.2258 2006 -16.9687 2007 -17.85947 2008 -25.12112 2009 -21.56591 2010 -18.30156 2011 -18.94327 2012 -21.46611 2013 -18.06428 2014 -17.21222 2015 -16.24319 2016 -14.73765 2017 -13.73454