Year	% of total
1971	1.188858695652174
1972	1.0723860589812333
1973	0.9718670076726342
1974	0.7544414699440253
1975	0.9779338014042127
1976	1.11348021795783
1977	1.1473565804274466
1978	1.3782136231115822
1979	1.1315115286080273
1980	0.7711115290577393
1981	0.6510416666666667
1982	0.5634936606963171
1983	0.9331259720062209
1984	1.8013100436681224
1985	1.027170311464546
1986	0.6815084052703316
1987	0
1988	0
1989	0
1990	0
1991	0
1992	0
1993	0.34848724853476953
1994	0.4582651391162029
1995	0.3106605624591236
1996	0.03017956843217142
1997	0.5082776648271856
1998	0
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0
2009	0.22326412145568209
2010	10.779974427067964
2011	24.33928571428571
2012	12.08416500332668
2013	10.40323207210007
2014	18.19794800586284
2015	38.84779392568097