Year	Percent
1960	4.91483
1961	5.21896
1962	4.84371
1963	4.58893
1964	4.37042
1965	4.16443
1966	3.99167
1967	3.83336
1968	3.69946
1969	3.57748
1970	3.4761
1971	3.38214
1972	3.28692
1973	0.98935
1974	1.01723
1975	1.07436
1976	1.10787
1977	1.1192
1978	0.79859
1979	1.22971
1980	1.1725
1981	0.96834
1982	0.70603
1983	0.403
1984	1.78873
1985	1.55954
1986	1.50367
1987	1.48184
1988	1.42144
1989	1.49127
1990	1.43472
1991	0.79886
1992	1.03216
1993	0.9034
1994	1.11707
1995	0.57612
1996	0.73825
1997	0.96662
1998	0.76759
1999	0.98428
2000	0.69489
2001	0.52956
2002	0.43059
2003	0.45951
2004	0.36222
2005	0.32882
2006	0.20009
2007	0.19103
2008	0.09374
2009	-0.00038
2010	-0.02886
2011	-0.10745
2012	0.00674
2013	-0.04605
2014	-0.08851
2015	-0.13802
2016	-0.15098
2017	-0.07858