Year	%
1975	83.93855
1977	82.34683
1978	81.00058
1982	90.09094
1983	89.20162
1984	91.20426
1985	93.80375
1986	96.16539
1987	94.62762
1988	95.77887
1989	97.86686
1991	98.56584
1993	97.43898
1994	99.62451
1995	100
1996	99.16463
1999	100
2000	100
2001	100
2002	100
2011	99.28668
2012	99.36185
2013	100
2014	99.07388
2015	98.21113
2016	97.76477
2017	96.75307