Year	Percent
1990	86.43
1991	86.69
1992	86.98
1993	86.95
1994	86.84
1995	86.66
1996	85.13
1997	86.15
1998	84.46
1999	84.46
2000	84.2
2001	82.59
2002	79.53
2003	79.12
2004	79.5
2005	78.14
2006	79.81
2007	78.95
2008	78.31
2009	78.58
2010	81.76
2011	80.83
2012	81.5
2013	81.49
2014	82.1
2015	82.44
2016	81.81
2017	83.24
2018	83.42
2019	83.99