Year	%
1975	95.49732
1976	94.77766
1979	94.82685
1980	95.18724
1981	94.15442
1982	94.16967
1983	94.90378
1984	95.59817
1985	96.44208
1986	96.09835
1987	95.37648
1988	95.16292
1989	95.65987
1990	96.34354
1991	96.51273
1992	96.01735
1993	95.89827
1994	95.2113
1995	95.19629
1996	95.62015
1997	95.49998
1998	95.40442
1999	95.33474
2000	96.69431
2001	96.76457
2002	96.69371
2003	96.6152
2004	96.65567
2005	96.56658
2006	96.63729
2007	96.70934
2008	96.72433
2009	96.55808
2010	96.58648
2011	96.53931
2012	96.62424
2013	96.75222
2014	96.71308
2015	96.56074
2016	96.76229
2017	96.85592