Year	Percent
1960	1.38643
1961	1.71292
1962	2.15479
1963	1.89737
1964	1.85768
1965	1.92917
1966	2.16827
1967	2.21499
1968	2.02216
1969	1.7027
1970	1.53695
1971	1.56569
1972	1.42149
1973	1.21209
1974	1.11742
1975	1.67638
1976	2.28106
1977	2.01486
1978	2.00238
1979	1.94171
1980	1.66667
1981	1.4761
1982	0.89423
1983	0.85872
1984	0.77297
1985	0.65951
1986	0.60125
1987	0.60411
1988	0.63082
1989	0.78736
1990	1.32121
1991	1.43516
1992	0.93404
1993	0.75675
1994	0.66752
1995	0.63511
1996	0.60693
1997	0.65787
1998	0.71992
1999	0.54752
2000	0.57282
2001	0.79044
2002	0.90003
2003	0.76385
2004	0.76717
2005	0.8036
2006	0.80274
2007	0.75067
2008	0.75496
2009	0.74355
2010	0.60186
2011	0.3189
2012	-0.07867
2013	-0.27033
2014	-0.21853
2015	-0.21713
2016	0.02006
2017	0.2846