Year	Percent
1960	0.684
1961	0.69362
1962	0.68847
1963	0.71941
1964	0.74202
1965	0.72513
1966	0.77826
1967	0.82271
1968	0.59448
1969	0.42051
1970	0.42587
1971	0.51212
1972	0.5965
1973	0.56935
1974	0.18553
1975	-0.25002
1976	-0.16137
1977	0.05371
1978	-0.06568
1979	-0.15515
1980	0.0154
1981	0.21372
1982	-0.333
1983	-0.56795
1984	-0.4174
1985	-0.36429
1986	-0.35409
1987	-0.3561
1988	-0.28117
1989	0.02599
1990	0.33249
1991	0.56707
1992	0.66571
1993	0.3863
1994	-0.05703
1995	-0.29074
1996	-0.31407
1997	-0.33615
1998	-0.34508
1999	-0.2623
2000	-0.22018
2001	-0.08163
2002	0.02537
2003	0.01667
2004	0.14603
2005	0.20461
2006	0.01587
2007	-0.16053
2008	-0.17399
2009	-0.22745
2010	-0.25317
2011	-0.15892
2012	0.51195
2013	0.91956
2014	1.11239
2015	1.449
2016	1.41006
2017	1.15278