Year	Percent
1960	1.33381
1961	1.29304
1962	1.24421
1963	1.19268
1964	1.14183
1965	1.0876
1966	1.04627
1967	0.99457
1968	0.89346
1969	0.72793
1970	0.52658
1971	0.30088
1972	0.11238
1973	0.02275
1974	0.07042
1975	0.21587
1976	0.39696
1977	0.55018
1978	0.65797
1979	0.69498
1980	0.67983
1981	0.6583
1982	0.65359
1983	0.64716
1984	0.64303
1985	0.64162
1986	0.63314
1987	0.62253
1988	0.62536
1989	0.64582
1990	0.6777
1991	0.70686
1992	0.72548
1993	0.73583
1994	0.7352
1995	0.72193
1996	0.7178
1997	0.70486
1998	0.64384
1999	0.52049
2000	0.35976
2001	0.17622
2002	0.02014
2003	-0.06421
2004	-0.04635
2005	0.0456
2006	0.16318
2007	0.26078
2008	0.3313
2009	0.35543
2010	0.34614
2011	0.33163
2012	0.32888
2013	0.33
2014	0.33807
2015	0.35048
2016	0.36227
2017	0.36935