Year	Percent
1990	79.13
1991	79.62
1992	80.67
1993	81.61
1994	82.51
1995	83.4
1996	83.46
1997	83.82
1998	84.65
1999	85.13
2000	85.33
2001	85.34
2002	86.69
2003	87.06
2004	84.62
2005	85.77
2006	86.18
2007	86.57
2008	86.53
2009	86.99
2010	87.15
2011	87.6
2012	88.15
2013	88.32
2014	88
2015	88.02
2016	88.37
2017	88.67
2018	88.46
2019	89.03