Year	% of total
1992	69.22884884884886
1993	74.94751588310038
1994	78.8367859554355
1995	73.92714701601165
1996	66.27915671117357
1997	69.04602729885057
1998	75.58357579877634
1999	70.2866612244898
2000	63.84976213130352
2001	66.07177578475336
2002	65.16932263814617
2003	57.209118432769365
2004	57.08327455919395
2005	54.933546375682
2006	53.45596006144393
2007	53.07573050719152
2008	58.93593415007658
2009	56.30680068434559
2010	51.94916666666667
2011	51.9388429054054
2012	53.20684828164291
2013	54.01785525154457
2014	62.53484346224677
2015	64.76047877145437
2016	67.28290178571429