Year	Percent
1990	80.61
1991	80.52
1992	80.66
1993	80.36
1994	80.21
1995	80.36
1996	80.82
1997	81.03
1998	81.16
1999	81.53
2000	81.62
2001	82.53
2002	84.01
2003	84.55
2004	84.61
2005	84.25
2006	83.96
2007	83.51
2008	83.92
2009	84.64
2010	84.68
2011	83.86
2012	84.02
2013	84.14
2014	84.22
2015	84.37
2016	84.59
2017	84.79
2018	84.93
2019	85.1