Year	Percent
1990	59.88
1991	60.24
1992	60.08
1993	60.18
1994	60.48
1995	60.26
1996	60.51
1997	60.7
1998	60.43
1999	60.5
2000	60.82
2001	62.11
2002	62.02
2003	63.05
2004	63.42
2005	63.02
2006	63.22
2007	63.57
2008	63.41
2009	63.6
2010	64.07
2011	63.19
2012	62.83
2013	62.69
2014	63.25
2015	62.63
2016	62
2017	62.29
2018	63.23
2019	63.78
2020	63.47