Year	Percent
1990	62.22
1991	62.48
1992	62.72
1993	62.78
1994	62.68
1995	62.68
1996	62.52
1997	62.46
1998	62.66
1999	62.58
2000	62.51
2001	62.39
2002	62.19
2003	61.62
2004	61.71
2005	61.89
2006	61.98
2007	61.92
2008	61.88
2009	62.26
2010	62.19
2011	62.9
2012	62.43
2013	62.15
2014	62.81
2015	62.21
2016	62.23
2017	59.67
2018	59.58
2019	60.03
2020	57.03