Year	Percent
1990	78.88
1991	79.01
1992	79.28
1993	79.62
1994	80.86
1995	80.66
1996	80.4
1997	80.36
1998	80.16
1999	80
2000	78.8
2001	83.54
2002	82.87
2003	81.94
2004	80.58
2005	80.99
2006	81.42
2007	81.78
2008	82.17
2009	82.56
2010	85.23
2011	85.87
2012	83.45
2013	80.76
2014	80.66
2015	80.33
2016	82.36
2017	82.25
2018	82.16
2019	82.04
2020	79.35