Year	Percent
1990	83.19
1991	83.16
1992	83.2
1993	83.24
1994	83.32
1995	83.43
1996	83.33
1997	83.34
1998	83.85
1999	83.95
2000	84
2001	84.1
2002	84.25
2003	84.38
2004	84.5
2005	84.61
2006	84.68
2007	84.76
2008	84.84
2009	84.91
2010	84.97
2011	84.94
2012	85.04
2013	85.09
2014	85.17
2015	85.21
2016	85.22
2017	85.25
2018	85.32
2019	85.39