Year	Percent
1960	1.87256
1961	2.61853
1962	3.24233
1963	3.58208
1964	3.63189
1965	3.37739
1966	3.1774
1967	3.0143
1968	3.0686
1969	3.42671
1970	3.86384
1971	4.40274
1972	4.71063
1973	4.79777
1974	4.55363
1975	4.17168
1976	3.74507
1977	3.39894
1978	3.34707
1979	3.50415
1980	3.86087
1981	4.21712
1982	4.40713
1983	4.57997
1984	4.67245
1985	4.7329
1986	4.76553
1987	4.73394
1988	4.43146
1989	3.89693
1990	3.18783
1991	2.45802
1992	1.84568
1993	1.34776
1994	1.04748
1995	0.86623
1996	0.75379
1997	0.56454
1998	0.44973
1999	0.29614
2000	0.15349
2001	0.046
2002	-0.04792
2003	-0.08056
2004	-0.08062
2005	-0.03649
2006	0.04417
2007	0.11323
2008	0.15524
2009	0.19514
2010	0.20049
2011	0.22293
2012	0.23003
2013	0.24655
2014	0.19869
2015	0.18132
2016	0.13577
2017	0.11489