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
1987	0
1988	0
1989	0
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	0
1998	0
1999	0.7331661200077175
2000	8.912037037037036
2001	8.570940754652552
2002	15.797124858665807
2003	13.705224408891405
2004	14.510466779352491
2005	13.231457323891165
2006	13.507225079598333
2007	12.894015532206488
2008	13.064923147510896
2009	8.102133303857633
2010	13.156415157989429
2011	12.96155102929964
2012	13.153421164470888
2013	15.786290322580646
2014	17.28797763280522
2015	21.36010128413818