Year	% of total
1971	7.954545454545454
1972	7.8431372549019605
1973	8.333333333333332
1974	9.090909090909092
1975	7.6190476190476195
1976	7.017543859649122
1977	4.807692307692308
1978	1.5151515151515151
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
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	14.285714285714285
2004	16.876574307304786
2005	18.013856812933028
2006	17.880794701986755
2007	17.69041769041769
2008	18.655097613882862
2009	34.50834879406308
2010	43.75
2011	38.12838360402166
2012	41.94117647058824
2013	43.18314803978935
2014	45.28735632183908
2015	46.655132641291814