Year	Percent
1976	0.82099
1977	0.82608
1978	0.83048
1979	0.8182
1980	0.81198
1981	0.79498
1982	0.78107
1983	0.77762
1984	0.78162
1985	0.78735
1986	0.80862
1987	0.82645
1988	0.83313
1989	0.84264
1990	0.84856
1991	0.86037
1992	0.87417
1993	0.88127
1994	0.90197
1995	0.9157
1996	0.92874
1997	0.93604
2001	0.96569
2003	0.96602
2006	0.98933
2007	0.9927
2008	0.99811
2009	1.0046
2010	0.99035
2011	0.99403
2012	0.99883
2013	1.00781
2014	1.01124
2015	1.01338
2016	1.01194