Year	Percent
1960	2.87028
1961	2.85138
1962	2.82487
1963	2.76381
1964	2.66715
1965	2.72894
1966	2.58876
1967	2.45949
1968	2.3627
1969	2.30091
1970	2.17431
1971	2.04071
1972	2.02126
1973	1.98029
1974	1.92251
1975	1.81218
1976	1.73548
1977	1.66373
1978	1.60583
1979	1.51691
1980	1.43329
1981	1.48252
1982	1.28887
1983	1.30594
1984	1.3092
1985	1.22296
1986	1.24101
1987	1.25555
1988	1.30415
1989	0.96721
1990	0.28802
1991	0.26722
1992	0.34602
1993	0.11382
1994	-0.43919
1995	-0.73209
1996	-0.82919
1997	-0.85293
1998	-0.83707
1999	-0.88478
2000	-0.9485
2001	-0.94892
2002	-0.84494
2003	-0.59764
2004	-0.50682
2005	-0.44768
2006	-0.41239
2007	-0.33526
2008	-0.2806
2009	-0.18521
2010	-0.26016
2011	-0.22399
2012	-0.1118
2013	-0.09259
2014	-0.34468
2015	-0.12605
2016	-0.19681
2017	-0.25328