Year	% of total
1970	5.5529224711048135
1971	5.721386258881474
1972	6.449079644428482
1973	6.391255724068396
1974	7.238857998095153
1975	7.660273994891069
1976	6.91923079612112
1977	7.543458794303707
1978	8.42261096079673
1979	9.216533626807117
1980	9.482158447746396
1981	8.152433507266492
1982	9.56770192701927
1983	9.987205645660516
1984	9.985935194863371
1985	9.96127020096607
1986	10.401976637614492
1987	10.325793409916049
1988	7.712935117010613
1989	7.569925438695291
1990	0
1991	0
1992	0
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	50
2008	50