Year	% of total
1990	96.9
1992	95.8
1995	98.5
1997	97.2
1998	97.5
1999	97.5
2000	99.1
2001	98.4
2002	98.9
2003	98.7
2004	99.1
2005	99.1
2006	99.4
2007	99.4
2008	94.8
2009	97.9
2010	95
2011	97.1
2012	98.2
2013	97
2014	99.6
2015	99.6
2016	98.4
2017	93.9
2018	99.5
2019	99.6
2020	98.8