Year	% of total
1993	61
1998	64.6
2001	66.9
2002	72.6
2003	74.1
2004	76
2005	78.6
2006	79.3
2007	73.7
2008	85.3
2010	88
2011	89.7
2012	87
2013	92.4
2014	93.4
2015	94
2016	94.1
2017	94.1