Year	Percent
1990	80.06
1991	83.22
1992	83.36
1993	83.01
1994	83.6
1995	83.37
1996	83.51
1997	84.08
1998	84.49
1999	85.23
2000	85.47
2001	85.64
2002	85.81
2003	86.15
2004	85.95
2005	86.44
2006	87.15
2007	87.29
2008	87.08
2009	87.19
2010	87.34
2011	87.73
2012	87.73
2013	87.7
2014	87.58
2015	87.58
2016	87.39
2017	87.36
2018	87.71
2019	88.07