Year	Percent
1971	0.8776
1972	0.88086
1973	0.88133
1974	0.88223
1975	0.88392
1976	0.88597
1977	0.89025
1978	0.89829
1979	0.91144
1980	0.93433
1981	0.94938
1982	0.95448
1983	0.95756
1984	0.96712
1985	0.97535
1986	0.98084
1987	0.99354
1988	0.97802
1989	0.98057
1990	0.98374
1991	0.98801
1992	0.99184
1993	0.99769
1994	0.9974
1995	1.0122
1996	1.01533
1997	1.01044
1998	1.01167
1999	1.01012
2000	1.00986
2001	1.01048
2002	1.01014
2003	1.00992
2004	1.00949
2005	1.00752
2006	1.00233
2007	0.9998
2008	0.99941
2009	0.99857
2010	0.99767
2011	0.99734
2012	0.99895
2013	1.00071
2014	1.00197
2015	1.00276