Year	% of total
1989	92.7
1990	93
1991	92.6
1992	86.4
1993	87.2
1994	89.1
1995	89.1
1996	91.2
1997	98.8
1998	99.1
1999	99
2000	99.1
2001	99
2002	98
2003	98.8
2004	99.3
2005	99.8
2006	99
2009	99.3
2018	99.8