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	0.000833748993547804
1987	0.0011450869040551335
1988	0.002067895397333372
1989	0.0018737424599593344
1990	0.009261476757202475
1991	0.010356792119173475
1992	0.021824145303353793
1993	0.02303510721314856
1994	0.04309868472442798
1995	0.10551582519843211
1996	0.1761780340345311
1997	0.18605970838976835
1998	0.18982303707334136
1999	0.37882688956113025
2000	0.4448757354804299
2001	0.5760287699169292
2002	0.720034079927099
2003	0.8943561902166525
2004	1.0533408523418715
2005	1.2904650733827172
2006	1.6661456970244106
2007	1.9826073557243644
2008	2.3363663724597377
2009	2.8468791767601647
2010	2.998097440777675
2011	3.4358633186029386
2012	4.039171945355719
2013	4.349665885329075
2014	4.587271868354881
2015	4.767945940872504