Year	Percent
1960	4.05716
1961	4.06714
1962	3.82299
1963	3.618
1964	3.58809
1965	3.52363
1966	3.48195
1967	3.41772
1968	3.3021
1969	3.05101
1970	3.12638
1971	3.56733
1972	3.51465
1973	3.31615
1974	3.20931
1975	3.08525
1976	2.99961
1977	2.90491
1978	2.78701
1979	2.24344
1980	1.7628
1981	1.85705
1982	1.96106
1983	2.03649
1984	2.03579
1985	2.03656
1986	2.11919
1987	2.17005
1988	2.16992
1989	1.3325
1990	0.28073
1991	0.08128
1992	-0.19598
1993	-0.56311
1994	-0.78154
1995	-0.85889
1996	-0.84956
1997	-0.8256
1998	-0.81383
1999	-0.79892
2000	-0.79294
2001	-0.92406
2002	-0.93885
2003	-0.94854
2004	-1.25947
2005	-1.64487
2006	-1.48993
2007	-1.08155
2008	-0.92223
2009	-1.11932
2010	-2.22415
2011	-2.28247
2012	-1.15704
2013	-0.82971
2014	-0.67788
2015	-0.75913
2016	-1.06863
2017	-1.2