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	7.823308993082244
1986	5.600191296030607
1987	6.4407793342994495
1988	19.324315319517556
1989	18.678938819707632
1990	7.565079139080705
1991	7.060349468944252
1992	7.767481044650379
1993	8.000631628812801
1994	6.702855794194005
1995	7.681447270812894
1996	6.983331772637888
1997	4.720677600244011
1998	4.8525902176795315
1999	5.286830269075988
2000	4.704029916842986
2001	4.382781274406211
2002	3.649600417368209
2003	4.162729162729162
2004	3.6064307439772127
2005	3.932047666696989
2006	4.744846380378885
2007	5.440529147355428
2008	5.293378790597523
2009	4.627073452726457
2010	4.274507247321642
2011	4.152090038582252
2012	5.058073380708045
2013	5.430820311593025
2014	4.564536407611822
2015	3.8242173074555823