Year	Percent
1990	60.26
1991	60.27
1992	61.17
1993	60.43
1994	61.45
1995	62.14
1996	62.17
1997	62.22
1998	62.29
1999	61.86
2000	62.24
2001	63.73
2002	62.6
2003	62.25
2004	62.18
2005	62.47
2006	63.66
2007	64.93
2008	65.49
2009	65.77
2010	65.48
2011	65.86
2012	65.39
2013	64.88
2014	65.39
2015	64.97
2016	64.68
2017	64.21
2018	63.9
2019	63.9
2020	60.95