Year	%
1970	92.88136
1971	85.1216
1973	91.70854
1976	96.69811
1977	97.15302
1979	95.12761
1980	98.5348
1981	97.76021
1982	96.77419
1983	97.82815
1984	100
1985	98.57143
1986	98.93491
1987	99.03498
1988	100
1991	99.53596
1992	100
1993	100
1997	98.4692
1998	97.2433
1999	98.01203
2000	99.36143
2001	99.13793
2002	100
2003	97.27385
2004	99.78177
2007	99.631
2008	97.86382
2009	98.1241
2010	98.13218
2013	99.42969
2014	100
2015	100
2016	99.07285
2017	97.23837