Year	% of total
1990	66.47979789720195
1991	68.00737382247773
1992	66.43532368389901
1993	66.895339528679
1994	64.83168091486779
1995	63.698991442216496
1996	60.58429468636155
1997	58.12331317740299
1998	67.35331200178321
1999	70.7249812609911
2000	67.75044494590995
2001	66.04481399981988
2002	60.90574661866728
2003	63.713608114940314
2004	62.75347216935279
2005	56.557262913223646
2006	54.33521232490001
2007	49.275356264730426
2008	52.12667458133143
2009	51.13112928161503
2010	49.97715170726494
2011	50.493286806315226
2012	50.702789125952485
2013	51.12640600493025
2014	50.30671135000902
2015	47.5277600350723
2016	47.241459002620864