Year	% of total
1971	1.6
1972	1.6
1973	0
1974	1.6
1975	1.6
1976	1.6
1977	1.6
1978	1.6
1979	1.6
1980	1.1661807580174928
1981	0.8456659619450317
1982	0.7054673721340388
1983	0.5865102639296188
1984	0.5333333333333333
1985	0.5221932114882507
1986	0.9009009009009009
1987	0.6717850287907869
1988	0.6386861313868614
1989	0.9717314487632509
1990	0.938566552901024
1991	0.9456264775413712
1992	0.8528784648187633
1993	0.9043927648578811
1994	0.841852074564041
1995	0.7629704984740591
1996	0.753650494583137
1997	0.7893643539675945
1998	0.8785942492012779
1999	0.903861955628595
2000	0.9044435705859222
2001	0.9305932531989143
2002	0.9255831173639394
2003	0.7834534628643058
2004	0.8884803921568627
2005	0.8884803921568627
2006	0.939963614311704
2007	0.9720176730486009
2008	0.9640666082383873
2009	1.0243632336655593
2010	1.0021097046413503
2011	0.9932885906040267
2012	0.94147582697201
2013	0.9086778736937756
2014	0.954283177984909
2015	1