Year	% of total
1990	91.1
1991	94.5
1992	96.5
1993	96.3
1994	97.7
1995	98.1
1996	97.5
1997	97.8
1998	98.5
1999	99.8
2000	99.7
2003	98.4
2005	99.2
2008	99.5
2009	99.4
2010	99.5
2011	99.5
2012	99.6
2013	99.7
2014	99.7
2015	99.8
2016	99.7
2017	99.8
2018	99.8
2019	99.8
2020	99.7
2021	99.7