Year	Percent
1971	0.91969
1972	0.93355
1973	0.9559
1974	0.949
1975	0.95811
1976	0.96341
1977	0.97036
1978	0.97311
1979	0.9789
1980	0.98059
1981	0.98605
1982	0.99737
1983	0.99751
1984	0.99748
1985	0.99975
1986	1.00226
1987	1.00524
1988	1.00748
1989	1.00949
1990	1.0034
1991	1.00209
1992	1.00169
1994	1.01838
1995	1.02
1996	1.01839
1997	1.01519
1998	1.00916
1999	1.00337
2000	0.99891
2001	0.99883
2002	0.99882
2003	0.99571
2004	0.98837
2005	0.98665
2006	0.98791
2007	0.99078
2008	0.98608
2009	0.99004
2010	0.98892
2011	0.98601
2012	0.98622
2013	1.00146
2014	1.00174
2015	1.0028
2016	0.99887