Year	% of total
1971	0.7723524021468778
1972	0.5779665015333805
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
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	0.049301561216105176
1996	0.05840582828686484
1997	0.056980056980056974
1998	0.04215518377025425
1999	0.05100089251561902
2000	0.030472797168373925
2001	0.029578394120725354
2002	0.06153846153846154
2003	0.05314512871750175
2004	9.181666278897607
2005	11.57771285132299
2006	17.969460817279163
2007	19.64790303390839
2008	26.98501806954142
2009	32.75159976730657
2010	37.47162533494905
2011	33.09036679569027
2012	16.770629970001426
2013	43.01555722253025
2014	48.43865620837649
2015	51.6130539034036