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
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	0.03168567807351077
1993	0.09288500835965074
1994	0.11290705966246731
1995	0.09088843444671665
1996	0.2167019027484144
1997	0.6653461323581695
1998	1.2165916275505317
1999	1.27728003675626
2000	1.432011151945254
2001	1.7497564144202664
2002	1.8918810127601338
2003	2.172076746711717
2004	3.0299424945468965
2005	4.846640131116835
2006	6.457442100604808
2007	7.638165691097784
2008	8.756854353350274
2009	11.467200801201804
2010	11.105195911413968
2011	17.36121337063761
2012	16.41059651449836
2013	19.66373411534702
2014	22.012554246745193
2015	25.093419694651054