Year	Percent
1960	1.55002
1961	1.60657
1962	1.39973
1963	1.23563
1964	1.2427
1965	1.22745
1966	1.2242
1967	1.20118
1968	1.12523
1969	0.92048
1970	1.03628
1971	1.24558
1972	1.08191
1973	0.95435
1974	0.9038
1975	0.84428
1976	0.81481
1977	0.78915
1978	0.72694
1979	0.54086
1980	0.45103
1981	0.57682
1982	0.70339
1983	0.80702
1984	0.82902
1985	0.85959
1986	0.96502
1987	1.04105
1988	1.06396
1989	0.79588
1990	0.368
1991	0.17012
1992	-0.10859
1993	-0.47411
1994	-0.694
1995	-0.76973
1996	-0.76034
1997	-0.73783
1998	-0.72444
1999	-0.70949
2000	-0.70339
2001	-0.82401
2002	-0.80277
2003	-0.81228
2004	-1.12299
2005	-1.6284
2006	-1.59638
2007	-1.18795
2008	-1.02848
2009	-1.11035
2010	-2.09694
2011	-2.25846
2012	-1.3412
2013	-1.01201
2014	-0.85983
2015	-0.94075
2016	-1.27069
2017	-1.42244