Year	% of total
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0
1966	0
1967	20.28571428571429
1968	28.443113772455092
1969	0
1970	12.938596491228072
1971	23.210831721470022
1972	19.617224880382775
1973	20.357941834451903
1974	20.84130019120459
1975	22.413793103448274
1976	15.129151291512915
1977	21.472392638036812
1978	13.921901528013583
1979	17.184942716857613
1980	10.625
1981	15.341959334565619
1982	18.848167539267017
1983	24.418604651162788
1984	32.90155440414508
1985	33.96029258098224
1986	38.2730455075846
1987	12.55868544600939
1988	15.34526854219949
1989	17.305151915455745
1990	13.627364864864866
1991	14.186204379562042
1992	25.38692307692308
1993	25.884705882352936
1994	25.951076923076922
1995	25.81568
1996	26.10406779661017
1997	25.668999999999997
1998	25.145142857142854
1999	29.514878048780485
2000	29.050259740259744
2001	25.804814814814815
2002	49.67118181818182
2003	34.49696296296296
2004	20.119823008849558
2005	20.123780487804876
2006	17.011855670103092
2007	13.052033898305085
2008	6.765990888382688
2009	4.522633333333333
2010	3.129850057670127
2011	2.5124632952691686
2012	2.947636363636364
2013	3.4903290246768504
2014	3.4744942381562103
2015	3.533904881101377
2016	4.317036535859269