Year	Percent
1960	0.95294
1961	0.95816
1962	0.87526
1963	0.81038
1964	0.81609
1965	0.73191
1966	0.6547
1967	0.62975
1968	0.71196
1969	0.76851
1970	0.65473
1971	0.55
1972	0.46521
1973	0.52063
1974	0.66797
1975	0.48274
1976	0.43316
1977	0.5191
1978	0.1118
1979	0.13501
1980	0.40249
1981	0.33327
1982	0.29581
1983	0.24955
1984	0.23397
1985	-0.00147
1986	-0.02652
1987	0.14711
1988	0.11237
1989	-1.17004
1990	-1.80375
1991	-0.99043
1992	-1.07385
1993	-0.79767
1994	-0.33959
1995	-0.4454
1996	-0.51573
1997	-0.6088
1998	-0.6673
1999	-0.56065
2000	-0.4939
2001	-1.99063
2002	-2.1707
2003	-0.79211
2004	-0.7548
2005	-0.75298
2006	-0.75951
2007	-0.73528
2008	-0.70192
2009	-0.64428
2010	-0.65828
2011	-0.64123
2012	-0.57922
2013	-0.55965
2014	-0.56839
2015	-0.63807
2016	-0.70138
2017	-0.72982