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	0.03938170719700699
1995	0.03575046177679795
1996	0.054455849919677626
1997	0.030153026610045985
1998	0.04810236182596565
1999	0.03861749372465727
2000	0.037535879885184364
2001	1.8023379383634432
2002	18.096849402686363
2003	24.81866263694749
2004	22.131279375234556
2005	29.807131366344336
2006	28.82200658647835
2007	31.519350455452855
2008	32.18625145919995
2009	32.11672938098545
2010	28.81225827403974
2011	29.766103851046605
2012	26.93599923204564
2013	24.966120160497436
2014	24.19041702259843
2015	22.90658027252982