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	0.3912669222943892
1987	11.54322346337974
1988	12.380432460658422
1989	9.760392763754735
1990	9.11446223344184
1991	8.772239636219153
1992	9.796308800360116
1993	10.128989408186808
1994	11.391286071066492
1995	10.769077890459812
1996	13.351101897781398
1997	14.327327408447916
1998	12.568670193317875
1999	12.59274351007657
2000	10.210864878728433
2001	10.873819698062672
2002	12.66631089980716
2003	12.38144356932437
2004	16.202142864936228
2005	16.024275924655946
2006	18.061500981927562
2007	19.337645719115766
2008	18.32065883370576
2009	15.559383274736756
2010	20.773154989350093
2011	22.251001340248013
2012	21.082995093561358
2013	26.92645907814037
2014	23.8992719825012
2015	22.368933735839164