Year	% of total
1990	15.622267560477995
1991	17.941810344827587
1992	36.64156356464049
1993	30.999521759923482
1994	34.14368650217707
1995	15.182732401275448
1996	10.338110477250591
1997	10.10749685885802
1998	12.736279494198932
1999	12.638292333723806
2000	17.376077586206897
2001	19.749171111431455
2002	6.338707454871159
2003	8.435754189944134
2004	12.03061813980358
2005	13.279207375808449
2006	26.732537395361604
2007	17.882861257801245
2008	15.130722820300486
2009	12.935265248889927
2010	7.1612011062821015
2011	22.532862468118502
2012	25.49767921609077
2013	17.775126752162244
2014	19.631665220325907
2015	21.960675713098865