Year	Percent
1990	63.42
1991	63.92
1992	64.21
1993	64.04
1994	63.82
1995	63.62
1996	63.7
1997	63.89
1998	63.56
1999	63.05
2000	62.59
2001	62.24
2002	61.55
2003	61.17
2004	60.71
2005	60.61
2006	60.53
2007	60.7
2008	60.58
2009	60.37
2010	60.08
2011	59.59
2012	59.28
2013	59.61
2014	59.82
2015	59.99
2016	60.45
2017	60.87
2018	61.88
2019	62.36
2020	62.34