Year	Percent
1990	76.02
1991	76.08
1992	76.26
1993	76.76
1994	76.53
1995	76.46
1996	76.46
1997	76.32
1998	76.59
1999	76.73
2000	76.95
2001	77.02
2002	77.02
2003	76.95
2004	77.08
2005	77.31
2006	77.32
2007	77.43
2008	77.42
2009	77.38
2010	77.34
2011	77.29
2012	77.26
2013	77.25
2014	77.25
2015	77.28
2016	77.31
2017	77.38
2018	77.44
2019	77.49