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	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0.2527181898325008
1986	0.6679276510225796
1987	0.9272336505987103
1988	1.2384296201723588
1989	1.7102482831484416
1990	2.474451733833177
1991	2.6028668879056047
1992	2.810828193832599
1993	3.0758414439922133
1994	2.9529098991280556
1995	2.966094796496651
1996	2.909402985074627
1997	3.188973509933775
1998	3.1040061686086364
1999	3.169486642221058
2000	3.338016141141141
2001	3.8206647619047613
2002	3.774253980007405
2003	3.6869293478260867
2004	3.7771673819742486
2005	3.8415494921330415
2006	4.131936605316974
2007	4.426226134917268
2008	4.100047670639221
2009	5.815205223880597
2010	6.978956991481406
2011	5.954043507512894
2012	5.472225385527877
2013	5.398764488286067
2014	4.651744245524297
2015	4.228275510204081
2016	4.83072183552462