Year	% of total
1990	66
1996	60.8
1998	60.8
1999	85.6
2000	85
2001	85.9
2002	85.8
2003	85.9
2004	77.2
2005	87.5
2006	90.5
2007	90.6
2008	87.2
2009	93.8
2010	95.6
2011	95.8
2012	95.7
2013	96.8
2014	96.4
2015	96.3
2016	95.5
2017	97.3
2018	97.7
2019	92.2