Year	% of total
1981	21.828358208955223
1982	18.007662835249043
1983	14.038876889848812
1984	11.157894736842106
1985	4.722792607802875
1986	8.375209380234507
1987	5.518763796909492
1988	15.841584158415841
1989	13.089622641509436
1990	11.920529801324504
1991	3.5294117647058822
1992	2.6690391459074734
1993	2.9359430604982206
1994	2.4816176470588234
1995	2.0172910662824206
1996	2.7741083223249667
1997	3.129074315514994
1998	2.127659574468085
1999	2.3914968999114263
2000	2.368421052631579
2001	2.1257750221434897
2002	2.530541012216405
2003	2.783109404990403
2004	5.236139630390143
2005	0.5703422053231939
2006	0.6103763987792472
2007	0.7246376811594203
2008	0
2009	0
2010	0
2011	8.577405857740587
2012	28.57142857142857
2013	17.551462621885157
2014	4.280155642023346
2015	3.606336366700371