Year	% of total
1971	0
1972	0
1973	0
1974	0.5034752545601773
1975	1.15036679483948
1976	1.0740971581237224
1977	0.6190596675473204
1978	1.002548235532902
1979	0.835524431648159
1980	0.6643141576916648
1981	0.769678756948959
1982	0.4815031357345661
1983	0.8278976100191732
1984	1.420162187403861
1985	1.941749758918876
1986	1.1604528865476602
1987	1.3961114450097933
1988	1.1491346364363928
1989	1.2560916664846644
1990	2.121369234183306
1991	2.152757709516646
1992	1.9776297048635478
1993	1.9326012141443514
1994	1.749389802548179
1995	2.392237848014364
1996	2.2471063007296217
1997	2.5781130783897477
1998	2.2650213182617143
1999	2.3068139990379115
2000	2.1216565415701774
2001	3.144565879829983
2002	2.9846666875038856
2003	3.0191829041663443
2004	2.635279443053309
2005	2.420707718772298
2006	2.7359378642078753
2007	2.430408699674463
2008	2.424922138494677
2009	2.456220804066334
2010	2.038382773141962
2011	2.25681270025796
2012	2.118049606986531
2013	2.2216612454989217
2014	2.008784386795538
2015	0.7503299763568745