Year	% of total
1960	0
1961	0
1962	0
1963	0
1964	0
1965	0
1966	0
1967	0
1968	0
1969	0
1970	0
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	7.340225563909774
1980	15.237554419837213
1981	32.282268021654474
1982	47.05603038936373
1983	52.64280415430267
1984	53.568885724457104
1985	50.7622860063027
1986	22.483139676606807
1987	18.283316177052818
1988	27.359441644048083
1989	30.833456479976356
1990	27.6969569189683
1991	25.13060951105157
1992	23.11787072243346
1993	28.082234194067745
1994	26.479676729260753
1995	29.31152010906612
1996	33.25052854122622
1997	33.36380720199096
1998	30.7740205000479
1999	31.96875717895704
2000	39.12896548810881
2001	37.13462163039948
2002	43.58974358974359
2003	52.443586340050686
2004	51.13622843545509
2005	45.16506672910325
2006	50.837144121551844
2007	55.5284231694617
2008	55.90477464223619
2009	58.294584734244225
2010	64.27810902896081
2011	56.81048446473274
2012	52.08724807486828
2013	51.335288367546426
2014	48.95768753874768
2015	44.01224242855618