Year	Percent
1960	4.44252
1961	4.18927
1962	3.89365
1963	3.55812
1964	3.1902
1965	2.81379
1966	2.42166
1967	2.06368
1968	1.80619
1969	1.67699
1970	1.6369
1971	1.63022
1972	1.60398
1973	1.5485
1974	1.44545
1975	1.31517
1976	1.18018
1977	1.07591
1978	1.02123
1979	1.03093
1980	1.0838
1981	1.12912
1982	1.15246
1983	1.18124
1984	1.21383
1985	1.23433
1986	1.27677
1987	1.27905
1988	1.13741
1989	1.65671
1990	0.60434
1991	0.62503
1992	-0.06935
1993	-0.66328
1994	-1.45085
1995	-1.75226
1996	-1.51456
1997	-1.57996
1998	-1.72609
1999	-0.95251
2000	-0.30055
2001	-0.17007
2002	0.00413
2003	0.3364
2004	0.69492
2005	0.88889
2006	1.05766
2007	1.14386
2008	1.21837
2009	2.637
2010	1.41327
2011	1.43151
2012	1.40868
2013	1.43945
2014	1.47268
2015	1.46148
2016	1.42205
2017	1.35966