Year	Percent
1970	0.9218
1971	0.91597
1972	0.92056
1973	0.9163
1974	0.92139
1975	0.92561
1976	0.93634
1977	0.92733
1978	0.93396
1979	0.9396
1980	0.97506
1983	0.97616
1984	0.99303
1988	1.01082
1989	0.98758
1991	1.00623
1992	1.00005
1993	0.995
1998	0.95807
1999	0.94814
2000	0.94996
2001	0.95791
2002	0.95108
2003	0.96659
2004	0.97021
2005	0.97251
2006	0.97686
2007	1.00101
2008	0.97577
2009	0.97262
2010	0.96614
2011	0.96284
2012	0.96341
2013	0.97042
2014	0.97706
2015	0.97842
2016	0.97608