Year	Percent
1971	0.93956
1972	0.94664
1973	0.9544
1974	0.95679
1975	0.95924
1976	0.96683
1977	0.96815
1978	0.97307
1979	0.97908
1980	0.98175
1981	0.98594
1982	0.98844
1983	0.98992
1984	0.98963
1985	0.99544
1986	0.98227
1987	0.9813
1988	0.97248
1989	0.97386
1990	0.96999
1991	0.97024
1992	0.97031
1993	0.98655
1994	0.95443
1995	0.96304
1996	0.96045
1997	0.96833
1998	0.97092
1999	0.96548
2000	0.96791
2001	0.97342
2002	0.97552
2003	0.98123
2004	0.97964
2005	0.97888
2006	0.98039
2007	0.98107
2008	0.98317
2009	0.98642
2010	0.99124
2011	0.99332
2012	0.99076
2015	1.0088
2016	1.0097