Year	Percent
1975	9.78293
1976	7.35922
1977	6.80721
1978	8.95632
1979	8.99972
1980	7.78797
1981	6.19403
1982	5.06874
1983	6.81225
1984	7.73685
1985	14.2995
1986	19.90241
1987	16.65413
1988	21.87694
1989	32.98406
1990	24.55817
1991	28.22028
1992	23.3584
1993	34.47118
1994	32.46244
1995	31.22511
1996	36.49034
1997	46.41832
1998	65.54596
1999	100.69033
2000	106.19455
2001	85.33909
2002	64.71416
2003	73.67234
2004	73.6909
2005	80.07342
2006	104.72951
2007	103.12839
2008	50.45283
2009	72.34291
2010	72.33439
2011	54.30742
2012	67.37356
2013	81.85776
2014	73.13375
2015	85.64968
2016	87.58333
2017	106.45937