Year	Percent
1960	0.66832
1961	1.11139
1962	1.34157
1963	1.37848
1964	1.43768
1965	1.35946
1966	1.07801
1967	0.78774
1968	0.92584
1969	1.04878
1970	1.09615
1971	1.2334
1972	1.12391
1973	0.96003
1974	0.86527
1975	0.78546
1976	0.71274
1977	0.73604
1978	0.68561
1979	0.55625
1980	0.60335
1981	0.70472
1982	0.71988
1983	0.6871
1984	0.65219
1985	0.66706
1986	0.74351
1987	0.7781
1988	0.62162
1989	0.39814
1990	0.06649
1991	-0.50216
1992	-1.82418
1993	-2.57432
1994	-2.13859
1995	-1.7854
1996	-1.47536
1997	-1.14092
1998	-0.96056
1999	0.29448
2000	0.48371
2001	-0.63696
2002	-0.63343
2003	-0.62762
2004	-0.59782
2005	-0.57226
2006	-0.58966
2007	-0.45619
2008	-0.26813
2009	-0.19277
2010	-0.22806
2011	-0.30358
2012	-0.35794
2013	-0.35589
2014	-0.26226
2015	0.06555
2016	0.02911
2017	-0.02356