Year	% of total
1990	64.84273104457881
1991	64.66120273144088
1992	64.66811949874285
1993	65.32846322045806
1994	65.27872552056479
1995	62.59791677955522
1996	63.804125377739894
1997	63.092008209627856
1998	61.18523543332202
1999	60.73290517137003
2000	59.87002151468728
2001	59.75922036986813
2002	59.477607624544135
2003	60.607316820575726
2004	60.62312131987682
2005	62.28691528495097
2006	62.56755489215993
2007	62.27964290033193
2008	63.314744672844704
2009	62.443916241733184
2010	59.329668898819136
2011	62.17412290855609
2012	64.74116370704489
2013	61.31260222591183
2014	63.66758796294468
2015	63.057653954568785
2016	62.94886564757986