Year	% of total
1991	76.9
1995	79
1998	79
1999	83.8
2000	90.2
2002	97
2004	87.8
2005	89.3
2006	95.8
2007	90.7
2008	94.9
2009	93.5
2010	94
2011	96.2
2012	93.7
2013	93
2014	93.1
2015	93.5
2016	96.8
2017	95.3
2018	94.8
2019	95.3
2020	94.6