Year	% of total
1990	66.47979789720196
1991	68.00737382247773
1992	66.43532368389901
1993	66.895339528679
1994	64.8316809148678
1995	63.69899144221651
1996	60.58429468636157
1997	58.12331317740299
1998	67.3533120017832
1999	70.7249812609911
2000	67.75044494590995
2001	66.04481399981988
2002	60.90574661866725
2003	63.713608114940314
2004	62.75347216935278
2005	56.55726291322365
2006	54.3352123249
2007	49.275356264730426
2008	52.12667458133144
2009	51.131129281615046
2010	49.97715170726493
2011	50.493286806315226
2012	50.702789125952485
2013	51.126406004930246
2014	50.30671135000903
2015	47.52776003507229
2016	47.24145900262088