Year	% of total
1990	12.688653896431356
1991	12.080271978062774
1992	9.976366814250422
1993	8.431028137317286
1994	8.082842917561901
1995	8.029265968578732
1996	6.668426385426862
1997	6.045029351514085
1998	6.358203751029793
1999	5.345295109685709
2000	4.605126352167385
2001	3.864093063069915
2002	3.6880322061908903
2003	3.4436848041036123
2004	2.8800921762932195
2005	2.52441048718973
2006	2.5522600937069524
2007	2.0066310428511196
2008	1.7970793070184727
2009	1.8399075266347653
2010	0.8489998943085133
2011	1.6781123663997612
2012	1.7529861989646192
2013	0.6540917329165794
2014	0.7985383647772348
2015	0.882585206918012