Year	% of total
1971	5.615550755939525
1972	5.10879848628193
1973	6.191687871077184
1974	1.6516516516516515
1975	2.272727272727273
1976	3.3877038895859477
1977	1.7184035476718404
1978	1.392891450528338
1979	1.6969696969696972
1980	0.8207934336525308
1981	0.949367088607595
1982	1.1991164405175134
1983	0.8166713601802309
1984	1.7010309278350515
1985	2.6995027231825715
1986	1.20186957489428
1987	2.4706867671691795
1988	0.9419454056132257
1989	0.6646971935007385
1990	0.791602133884013
1991	1.8242122719734661
1992	1.0479272615194946
1993	0.9660377358490566
1994	0.5675368898978433
1995	0.5085408788629547
1996	0.8452125646524536
1997	0.5186844276788871
1998	0.7925151348376445
1999	0.9002700810243073
2000	0.604001510003775
2001	0.4740168539325843
2002	0.540494890634237
2003	1.4703277236492471
2004	1.289782244556114
2005	1.1452491904272963
2006	0.7043871066533957
2007	0.3566489555280588
2008	0.20887001322843415
2009	0.5179648570679255
2010	0.305399462496946
2011	0.32733224222585927
2012	0.609047118099773
2013	0.3264240248082259
2014	0.2916211008696558
2015	0.3506810327302297