Year	Percent
1974	79.66462
1980	93.84024
1981	91.53845
1982	91.5947
1983	95.12595
1984	94.43451
1985	93.36848
1987	92.64542
1988	92.82957
1989	90.43933
1990	89.00241
1991	90.53061
1993	94.02973
1998	97.78829
1999	94.3819
2000	100.72295
2002	92.64542
2003	93.57424
2004	98.30968
2005	103.46307
2006	100.41659
2007	98.78508
2008	100.08328
2009	100.68362
2010	98.13119
2011	100.96402
2012	108.32401
2013	104.84852
2014	104.53256
2015	103.84774
2016	101.54615