Year	%
1971	100
1972	96.78117
1973	100
1974	100
1975	98.59823
1976	100
1977	97.84232
1978	98.08847
1982	97.39594
1984	88.52327
1985	78.92989
1986	80.52178
1987	79.44251
1988	98.39435
1989	90.03215
1990	94.81287
1991	100
1992	100
1993	100
1994	99.92891
1995	98.13073
1996	99.96008
1997	98.06811
1998	99.60822
1999	96.60626
2000	97.51093
2001	100
2002	99.4278
2004	98.59872
2005	90.10204
2006	100
2007	100
2010	96.93654
2011	98.78772
2012	100
2014	100
2015	100
2016	100