Year	Percent
1990	56.79
1991	57.61
1992	58.49
1993	59.05
1994	59.34
1995	59.41
1996	59.61
1997	59.74
1998	59.9
1999	60.04
2000	60.22
2001	60.18
2002	60
2003	59.71
2004	59.32
2005	59.2
2006	59.08
2007	58.99
2008	59.03
2009	59.13
2010	59.02
2011	60.04
2012	59.4
2013	59.85
2014	60.26
2015	60.34
2016	59.29
2017	59.91
2018	60.51
2019	62.96
2020	62.97