Year	Percent
1971	0.95646
1972	0.95232
1973	0.95492
1974	0.95851
1989	0.98007
1990	0.97978
1991	0.99659
1992	1.0033
1993	0.99771
1994	1.01567
1995	1.01725
1996	1.01161
1997	1.00103
1998	1.00837
1999	1.01061
2000	1.01135
2001	1.0101
2002	1.011
2003	1.01098
2004	1.00906
2005	1.00848
2006	1.00411
2007	0.99737
2008	0.99296
2009	0.99448
2010	0.98959
2011	0.98565
2012	0.98531
2015	0.99041
2016	0.99039