Year	Percent
1990	82.23
1991	82.54
1992	83.9
1993	84.43
1994	85.19
1995	85.55
1996	85.68
1997	85.51
1998	85.38
1999	85.16
2000	84.99
2001	84.76
2002	84.51
2003	84.22
2004	83.62
2005	83.06
2006	82.44
2007	81.66
2008	80.94
2009	80.31
2010	79.84
2011	79.35
2012	78.79
2013	78.24
2014	77.76
2015	77.29
2016	76.96
2017	76.79
2018	76.55
2019	76.33