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
2000	0
2001	0
2002	0
2003	7.437269757419893
2004	5.062664907651715
2005	6.322523058613508
2006	9.614587650227932
2007	13.298261969767596
2008	13.591138232953037
2009	14.231970471323113
2010	21.077423207058978
2011	20.933407807360517
2012	22.69664226792146
2013	22.1436728478982
2014	22.59653493375609
2015	22.02958227230861