Year	Percent
1971	65.33495
1972	60.47272
1973	61.19996
1974	57.69036
1975	66.80051
1976	89.62924
1977	74.42194
1978	80.13523
1979	83.14713
1980	86.10832
1981	97.29003
1982	93.92162
1983	93.8021
1984	93.51004
1985	97.11229
1986	100.01039
1987	101.62141
1992	56.32535
1994	76.49034
1995	64.25276
1996	101.49389
1997	102.4864
1999	107.06777
2000	100.76105
2001	85.10557
2002	90.28004
2003	92.27233
2004	94.74692
2005	109.14656
2007	104.82556
2010	98.30975
2011	98.60736
2012	97.29817
2013	97.61565
2016	97.35903