Year	Percent
1960	1.83133
1961	1.68704
1962	1.54457
1963	1.49883
1964	1.58939
1965	1.72456
1966	1.93841
1967	2.05236
1968	1.98067
1969	1.68474
1970	1.2174
1971	0.69545
1972	0.23028
1973	0.01394
1974	0.08777
1975	0.39889
1976	0.75724
1977	1.05305
1978	1.12562
1979	0.91576
1980	0.51784
1981	0.08096
1982	-0.27234
1983	-0.56431
1984	-0.71697
1985	-0.77102
1986	-0.84272
1987	-0.901
1988	-0.87155
1989	-0.69938
1990	-0.44455
1991	-0.1185
1992	0.18052
1993	0.3376
1994	0.22864
1995	-0.00701
1996	-0.31295
1997	-0.55251
1998	-0.65654
1999	-0.5521
2000	-0.32526
2001	-0.00861
2002	0.2208
2003	0.38451
2004	0.4072
2005	0.35176
2006	0.25454
2007	0.20175
2008	0.17462
2009	0.21785
2010	0.29579
2011	0.38838
2012	0.45353
2013	0.49293
2014	0.52074
2015	0.52624
2016	0.51941
2017	0.51808