Year	Percent
1971	0.87234
1973	0.88035
1974	0.88134
1975	0.88906
1976	0.89743
1977	0.90692
1978	0.91516
1991	0.97224
1992	0.97406
1993	0.97469
2001	0.97653
2002	0.98509
2004	1.01291
2005	1.00291
2006	1.01593
2007	1.02392
2008	1.02396
2009	1.02938
2010	1.02684
2011	1.02876
2012	1.02692
2013	1.03643
2014	1.03701
2015	0.95294