Year	Percent
1990	58.64
1991	58.9
1992	59.91
1993	60.89
1994	61.25
1995	62.33
1996	62.37
1997	62.41
1998	62.54
1999	62.63
2000	62.94
2001	63.24
2002	63.54
2003	63.82
2004	64.27
2005	64.55
2006	63.67
2007	64.21
2008	65.77
2009	64.72
2010	63.52
2011	62.3
2012	64.19
2013	65.08
2014	64.66
2015	64.89
2016	65.38
2017	64.92
2018	66.63
2019	67.3
2020	62.61