Year	Percent
1971	96.97919
1972	93.91042
1973	95.60545
1974	94.32273
1981	93.37783
1982	91.31809
1983	92.58417
1984	97.35581
1985	100.50729
1986	96.85686
1987	98.4761
1988	102.96405
1989	97.10753
1990	95.6696
1991	98.01112
1992	97.28868
1993	99.57841
1994	97.35247
1998	101.8011
1999	101.35924
2000	99.89109
2001	101.52771
2002	105.9975
2004	100.93671
2005	100.41093
2006	102.27352
2007	101.99514
2008	101.36426
2009	98.21628
2010	99.36483
2011	99.68857
2012	98.99673
2013	100.00603
2014	99.23309
2015	98.31138
2016	102.66111