Year	Percent
1960	-0.90625
1961	-0.33291
1962	0.28335
1963	0.78587
1964	1.20379
1965	1.50708
1966	1.79469
1967	2.07244
1968	2.15625
1969	2.085
1970	1.91079
1971	1.6587
1972	1.41316
1973	1.2968
1974	1.29554
1975	1.39337
1976	1.58461
1977	1.66573
1978	1.55515
1979	1.18673
1980	0.6314
1981	-0.01731
1982	-0.55077
1983	-0.73221
1984	-0.38813
1985	0.33391
1986	1.18127
1987	1.85684
1988	2.16879
1989	2.01004
1990	1.53298
1991	0.97001
1992	0.54701
1993	0.26019
1994	0.2323
1995	0.36029
1996	0.51388
1997	0.61996
1998	0.73247
1999	0.78414
2000	0.83319
2001	0.8755
2002	0.92207
2003	0.96594
2004	1.00582
2005	1.02603
2006	1.04031
2007	1.05148
2008	1.0329
2009	1.00217
2010	0.93729
2011	0.85432
2012	0.79796
2013	0.74288
2014	0.70108
2015	0.6962
2016	0.68303
2017	0.65467