Year	Percent
1973	0
1974	0.01454
1975	0.02193
1976	0.12162
1977	1.02569
1978	1.30157
1979	1.39009
1980	12.57383
1981	15.15571
1982	23.2757
1983	15.20218
1984	15.5581
1985	18.70123
1986	18.749
1987	21.86818
1988	33.3446
1989	16.87427
1990	0.2807
1991	2.41606
1992	9.14591
1993	6.30111
1994	8.56389
1995	10.51139
1996	46.97266
1997	32.71931
1998	24.72846
1999	37.74623
2000	20.47636
2001	18.93351
2002	20.01768
2003	17.62476
2004	17.7408
2005	27.0385
2006	26.66677
2007	25.12362
2008	30.02859
2009	33.97506
2010	33.20736
2011	26.82484
2012	31.40669
2013	36.28757
2014	28.81446
2015	31.37712
2016	23.33345