Year	Percent
1990	63.42
1991	63.66
1992	63.84
1993	63.91
1994	63.87
1995	63.81
1996	63.7
1997	63.62
1998	63.82
1999	63.83
2000	63.75
2001	63.75
2002	63.37
2003	62.99
2004	63.12
2005	63.29
2006	63.47
2007	63.43
2008	63.48
2009	63.94
2010	63.89
2011	64.72
2012	64.29
2013	64.05
2014	64.78
2015	64.16
2016	64.17
2017	61.87
2018	61.77
2019	62.3