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	0.0009805315461511685
1987	0.0013520456450609774
1988	0.002455795677799607
1989	0.0022073593360263117
1990	0.010931500485085333
1991	0.012215901972085098
1992	0.026098742218571034
1993	0.0274356025440286
1994	0.051175370317773465
1995	0.12510031629136573
1996	0.20856328338197555
1997	0.2198113726469182
1998	0.22411866179918252
1999	0.4435934551184565
2000	0.5202847874626111
2001	0.6771840162129721
2002	0.8481544696004272
2003	1.0543346490749606
2004	1.2495778453225261
2005	1.5405446192025218
2006	1.9841454462744126
2007	2.3383760562337064
2008	2.741658857435861
2009	3.3264944369466107
2010	3.478093067705653
2011	3.954730227744813
2012	4.643608604789284
2013	4.960653326078633
2014	5.173682558774104
2015	5.361011247979037