Year	% of total
1990	58.422598479613
1991	54.55863539445629
1992	33.15792136821333
1993	26.948716602803003
1994	18.319959023390815
1995	18.581318939216146
1996	18.581377655527596
1997	18.531717747683533
1998	19.7410823424825
1999	19.5587588028169
2000	19.845981068506337
2001	59.388508170795994
2002	58.226832789690384
2003	52.706003946255755
2004	59.05997056659308
2005	61.170863938440014
2006	64.84537342623152
2007	70.90676065363665
2008	81.73543408954397
2009	85.12295950816197
2010	81.4537680384821
2011	85.14831970040406
2012	89.89037758830695
2013	92.96480260340842
2014	93.86120996441281
2015	86.08230719377835