Year	Percent
1970	0.84033
1977	0.91614
1978	0.92282
1979	0.91689
1980	0.91554
1981	0.92909
1982	0.91753
1985	0.93976
1991	0.95926
1995	0.96026
1998	0.97072
1999	0.97238
2000	0.97016
2001	0.97288
2002	0.97367
2003	0.97856
2004	0.99489
2005	0.99724
2006	1.00191
2007	1.00409
2008	1.00806
2009	1.00327
2010	1.00821
2011	1.00334
2012	0.99022
2013	0.99718
2014	0.99915
2015	1.00042
2016	1.00061