Year	Percent
1960	-5.98637
1961	-4.95114
1962	-6.44148
1963	-7.80454
1964	-7.10583
1965	-7.63815
1966	-9.34952
1967	-12.10644
1968	-9.74194
1969	-9.65529
1970	-9.28474
1971	-10.04682
1972	-12.41575
1973	-10.28819
1974	-15.17789
1975	-18.88474
1976	-18.03727
1977	-18.60188
1978	-18.02028
1979	-19.50541
1980	-21.50559
1981	-28.02837
1982	-22.31526
1983	-17.81343
1984	-11.35255
1985	-12.99598
1986	-15.93958
1987	-15.68308
1988	-18.27935
1989	-11.30951
1990	-7.35758
1991	-9.33974
1992	-10.26245
1993	-10.45303
1994	-7.74644
1995	-9.06226
1996	-3.52017
1997	-4.35936
1998	-5.40775
1999	-17.29364
2000	-13.71091
2001	-16.57759
2002	-11.1085
2003	-10.75425
2004	-8.73315
2005	-7.95248
2006	-9.79583
2007	-12.63195
2008	-10.78864
2009	-11.95691
2010	-13.41753
2011	-12.81189
2012	-10.48269
2013	-13.15179
2014	-12.37629
2015	-11.57674
2016	-13.90221
2017	-17.52226