Year	Percent
1981	0.4977
1987	0.62198
1988	0.65204
1989	0.65482
1990	0.67222
1991	0.6971
1992	0.72985
1993	0.76464
1994	0.78842
1995	0.7971
1996	0.80837
1997	0.85032
1998	0.90783
1999	0.92619
2000	0.92811
2001	0.92417
2002	0.94437
2003	0.96473
2004	0.97957
2005	1.00119
2006	0.98823
2008	1.01203
2009	1.00693
2010	1.00809
2011	1.01045
2012	1.00278
2013	1.02091
2014	1.02085
2015	1.02082
2016	1.03929