Year	Percent
1960	3.66872
1961	5.39207
1962	5.19501
1963	5.00811
1964	4.89241
1965	4.6726
1966	3.83387
1967	3.2748
1968	3.29485
1969	3.28049
1970	3.10516
1971	2.5565
1972	2.43041
1973	2.43535
1974	2.53961
1975	2.31132
1976	2.09401
1977	2.04853
1978	1.61157
1979	1.59954
1980	1.83623
1981	1.13999
1982	1.09291
1983	1.0372
1984	1.01078
1985	0.7616
1986	0.60472
1987	0.67953
1988	0.64048
1989	-0.64928
1990	-1.28717
1991	-0.47952
1992	-0.56702
1993	-0.38988
1994	-0.003
1995	-0.11291
1996	-0.18433
1997	-0.27996
1998	-0.34101
1999	-0.23541
2000	-0.17116
2001	-1.60386
2002	-1.65443
2003	-0.2828
2004	-0.2495
2005	-0.25445
2006	-0.26769
2007	-0.24868
2008	-0.22047
2009	-0.16929
2010	-0.18831
2011	-0.1776
2012	-0.11634
2013	-0.09754
2014	-0.10841
2015	-0.17885
2016	-0.24426
2017	-0.27344