Year	Percent
1988	-11.04651
1989	-12.89855
1990	-7.27023
1991	0.96154
1992	-2.87481
1993	-13.08658
1994	-11.58193
1995	-6.34994
1996	-3.45819
1997	-6.65839
1998	-9.09443
1999	-1.43205
2000	-2.15063
2001	-10.37017
2002	-10.63105
2003	-10.11274
2004	-11.59487
2005	-25.80696
2006	-33.96551
2007	-48.07351
2008	-54.99204
2009	-39.33046
2010	-43.61816
2011	-46.88984
2012	-48.36661
2013	-50.46276
2014	-35.8038
2015	-31.79058
2016	-29.49365
2017	-25.18125