Year	Percent
1990	83.15
1991	83.15
1992	82.62
1993	82.07
1994	81.5
1995	80.91
1996	80.3
1997	79.67
1998	79.03
1999	78.37
2000	77.7
2001	77.02
2002	76.33
2003	75.62
2004	74.9
2005	74.15
2006	73.39
2007	72.69
2008	71.96
2009	71.18
2010	70.36
2011	69.5
2012	68.6
2013	67.65
2014	66.65
2015	66.64
2016	66.62
2017	66.58
2018	66.53
2019	66.47
2020	65.38