Year	% of total
1990	71.23458441750667
1991	80.39123210182541
1992	81.11037273084342
1993	79.42612726488353
1994	72.01705162617792
1995	78.87591418921545
1996	76.22550196399659
1997	70.51695437343143
1998	67.9529747928762
1999	68.86082791574326
2000	67.20281447385027
2001	68.5443931584213
2002	68.80032722563001
2003	68.47795476146692
2004	68.44992448335682
2005	66.18191581098874
2006	67.21341187384881
2007	65.4600651347635
2008	65.15934339484211
2009	63.18071864755984
2010	63.72182170546588
2011	62.60644406306045
2012	60.60931587255375
2013	61.368703270797305
2014	65.15509399340846
2015	56.583825893692065
2016	55.96786307661638