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	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	11.529680365296803
1990	16.359918200409
1991	16.85279187817259
1992	17.119838872104733
1993	17.217217217217218
1994	22.5140712945591
1995	22.12467076382792
1996	20.0164744645799
1997	19.347133757961785
1998	18.763961280714817
1999	18.52409638554217
2000	17.870722433460077
2001	22.316986496090973
2002	22.267206477732792
2003	22.620599739243808
2004	20.77922077922078
2005	20.71156289707751
2006	19.81981981981982
2007	19.492502883506344
2008	27.22283205268935
2009	34.71615720524017
2010	42.01550387596899
2011	46.88878000979912
2012	43.76155268022181
2013	40.26717557251908
2014	47.0970970970971
2015	46.048918156161804