Year	%
1979	95.11257
1980	95.39778
1981	94.23578
1982	94.15992
1983	94.97197
1984	95.69277
1985	96.73344
1986	96.43378
1987	96.48055
1988	96.70087
1989	96.88458
1990	96.41458
1991	96.68563
1992	95.92344
1993	95.51041
1994	94.8082
1995	95.71875
1996	95.9053
1997	96.17122
1998	96.5519
1999	96.84186
2000	97.06572
2001	97.04711
2002	97.0057
2003	96.90584
2004	96.91736
2005	96.62267
2006	96.4509
2007	96.69756
2008	96.66424
2009	96.49255
2010	96.49102
2011	96.56812
2012	96.51339
2013	96.58135
2014	96.61729
2015	96.65955
2016	96.61449
2017	96.69044