Year	% of total
1971	0
1972	0.044702726866338846
1973	0
1974	2.2737210319195453
1975	1.4722863741339491
1976	1.3395031660983925
1977	1.1669849352853807
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0.04590841271663032
1984	0.07791629563668745
1985	0.039135113981019466
1986	0.05573100501579045
1987	0.05326231691078562
1988	0.0943881928951433
1989	0.08585030828065246
1990	0.09656094481170616
1991	0.09176254676360557
1992	0.0943777807738978
1993	0
1994	0
1995	0
1996	0
1997	0
1998	0
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0
2009	0
2010	0
2011	0
2012	0
2013	0
2014	0
2015	0