Year	%
1975	95.35018
1976	94.73148
1977	94.85443
1978	94.99098
1979	94.9591
1980	95.28353
1981	94.1866
1982	94.16065
1983	94.93117
1984	95.63978
1985	96.57384
1986	96.25157
1987	95.90195
1988	95.90452
1989	96.25155
1990	96.37371
1991	96.59264
1992	95.96568
1993	95.70151
1994	95.00857
1995	95.4449
1996	95.754
1997	95.8227
1998	95.9595
1999	96.0647
2000	96.87371
2001	96.90159
2002	96.84673
2003	96.75693
2004	96.78452
2005	96.5923
2006	96.54562
2007	96.70425
2008	96.69534
2009	96.52666
2010	96.54045
2011	96.5533
2012	96.57038
2013	96.66911
2014	96.6651
2015	96.60867
2016	96.69039
2017	96.77449