Year	% of total
1990	76.04555510213615
1991	74.66596842440931
1992	77.04333144372355
1993	76.15534898139055
1994	73.70640861917337
1995	71.58561111229474
1996	68.14396685590137
1997	67.84567496782486
1998	69.86472047010363
1999	72.68850073374674
2000	68.35938511980248
2001	70.46298260830332
2002	70.28425079546612
2003	69.49480415713224
2004	65.36322658381133
2005	65.86364033398512
2006	64.90879782842939
2007	63.44615888733016
2008	63.88744046835464
2009	64.30643194526108
2010	62.35518315900242
2011	60.913455974805885
2012	62.06808337956396
2013	61.25153391954353
2014	61.022630587271806
2015	59.01479403970449
2016	58.70114082031901