Year	% of total
1986	89.8
1991	92.2
1996	95.3
1999	97.4
2000	97.6
2002	97.8
2006	95.5
2007	97.8
2010	97.8
2011	98.7
2012	98.8
2013	98.6
2014	98.6
2015	99.6
2016	99.8
2017	99.8
2018	99.7
2019	99.2