Year Percent 1986 0.19902 1987 -4.39549 1988 10.32071 1989 -9.19968 1990 -3.11946 1991 -9.11233 1992 -30.3194 1993 -17.76199 1994 -22.48771 1995 -13.68983 1996 -17.90799 1997 0.24771 1998 3.7715 1999 2.11954 2000 6.5348 2001 8.2681 2002 8.72819 2003 8.81963 2004 8.06595 2005 4.49981 2006 4.76264 2007 5.51167 2008 5.57743 2009 1.53461 2010 4.14731 2011 5.00466 2012 5.09168 2013 4.99997 2014 4.33967 2015 3.69484 2016 4.62003 2017 4.86238