Year	%
1992	69.7
1993	72.2
1994	76.3
1995	78.7
1996	83.7
1997	85.9
1998	87.1
1999	89.3
2000	89.4
2001	90.3
2002	90.1
2003	88.9
2004	89.7
2005	89.8
2006	89.7
2007	90.9
2008	91
2009	92.2
2010	94.1
2011	93.7
2012	95
2013	95.6
2014	96.2
2015	96.5
2016	96.6
2018	99.6