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	2.259168704156479
1997	9.449149576538112
1998	9.920367877972184
1999	10.250443699467562
2000	10.505641776100436
2001	10.11027364200052
2002	10.072165890198228
2003	8.897352194414218
2004	9.819642825536736
2005	9.349805598101426
2006	8.98288594350607
2007	12.499797318113275
2008	17.282468132274154
2009	20.352955438942864
2010	19.173856381662517
2011	18.947079791609543
2012	19.50862626331371
2013	19.847615142818096
2014	17.907426152572008