Year	Percent
1990	80.19
1991	80.21
1992	79.99
1993	79.79
1994	79.76
1995	80.43
1996	80.35
1997	80.24
1998	80.11
1999	79.94
2000	80.37
2001	80.65
2002	80.88
2003	81.17
2004	80.86
2005	81.99
2006	82.26
2007	82.78
2008	83.16
2009	82.95
2010	82.86
2011	83.12
2012	82.84
2013	82.96
2014	82.85
2015	83.42
2016	83.5
2017	83.99
2018	84.51
2019	85.02