Year	% of total
1986	96
1996	98.2
2002	100
2004	98.3
2005	98.6
2006	98.7
2007	98.7
2008	98.7
2009	98.7
2010	98.6
2011	98.8
2012	98.8
2013	98.7
2014	98.7
2015	99.9
2016	99.9
2017	99.9
2018	99.9
2019	99.9