Year	Percent
1990	62.7
1991	62.97
1992	64
1993	64.39
1994	64.95
1995	65.21
1996	65.31
1997	65.2
1998	65.12
1999	65
2000	64.91
2001	64.79
2002	64.68
2003	64.55
2004	64.21
2005	63.94
2006	63.65
2007	63.27
2008	62.95
2009	62.74
2010	62.67
2011	62.61
2012	62.52
2013	62.42
2014	62.34
2015	62.21
2016	62.1
2017	62.07
2018	61.93
2019	61.74
2020	59.29