Year	Percent
1990	58.97
1991	59.13
1992	59.56
1993	60.88
1994	61.62
1995	61.83
1996	61.13
1997	60.67
1998	60.36
1999	60.71
2000	61.2
2001	61.19
2002	60.46
2003	60.78
2004	61.29
2005	61.71
2006	62.15
2007	62.7
2008	62.75
2009	62.75
2010	63.03
2011	62.86
2012	63.56
2013	63.73
2014	64.15
2015	64.13
2016	64.23
2017	64.11
2018	64.08
2019	63.71
2020	62.18