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	0.10152284263959391
1987	0.5450372920252439
1988	0.827459393196445
1989	0.49519370812700264
1990	0.30236393622869706
1991	0.18796992481203006
1992	0.33921302578018997
1993	0.4620877966813695
1994	0.27580772261623326
1995	0.3205128205128205
1996	0.36315615714757343
1997	0.2713920817369093
1998	0.1927353595255745
1999	0.1977121875441322
2000	0.5288135593220339
2001	0.5696118691217379
2002	0.6517461878996557
2003	0.5128846634976233
2004	0.5910560945689751
2005	0.5904288377874456
2006	0.45863309352517984
2007	0.46919467733251286
2008	0.44804162451221274
2009	0.41339686098654704
2010	0.41280368139676527
2011	0.3755035160783778
2012	0.3675584478187515
2013	0.3186004750043445
2014	0.31833150384193193
2015	0.2787419795939834