Year	% of total
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	18.143831097426872
1983	32.86659700452804
1984	49.976133651551315
1985	54.41290824261276
1986	55.500810777098664
1987	51.34921083894326
1988	46.708350558081854
1989	47.63604361218403
1990	49.67939515743133
1991	52.91438133308544
1992	57.795100222717146
1993	61.71055160484335
1994	60.22375457359978
1995	62.08381265406738
1996	68.9280993513879
1997	70.76638176638177
1998	69.73521275194308
1999	66.89787071273747
2000	68.49112772790136
2001	74.92207230779732
2002	77.15384615384615
2003	76.72030781658553
2004	77.17591319613359
2005	74.40228797168841
2006	70.63174967364215
2007	69.30584473527662
2008	62.01536788182871
2009	62.450916230366495
2010	58.44412964448465
2011	58.89173746208884
2012	61.45580369188769
2013	52.32216822673755
2014	49.49106276618486
2015	45.40373057640208