Year	Percent
1990	83.34
1991	83.4
1992	83.42
1993	83.45
1994	83.36
1995	83.23
1996	83.11
1997	82.94
1998	82.75
1999	82.54
2000	82.34
2001	82.21
2002	82.08
2003	81.95
2004	81.83
2005	81.75
2006	81.75
2007	81.74
2008	79.94
2009	78.01
2010	75.99
2011	76.08
2012	76.16
2013	76.23
2014	76.28
2015	76.28
2016	76.28
2017	76.26
2018	76.2
2019	76.11
2020	74.67