Year	Percent
1991	57.22
1992	56.22
1993	55.78
1994	56.96
1995	58.29
1996	58.26
1997	58.02
1998	58.37
1999	58.67
2000	59.39
2001	59.27
2002	59.57
2003	60.02
2004	60.22
2005	61.31
2006	61.81
2007	62.51
2008	62.88
2009	61.94
2010	62.18
2011	62.29
2012	61.92
2013	61.41
2014	60.92
2015	61.21
2016	61.28
2017	61.59
2018	62.17
2019	62.53
2020	60.6