Year	Percent
1990	58.04
1991	58.19
1992	58.28
1993	58.2
1994	58.25
1995	58.53
1996	58.76
1997	58.85
1998	58.97
1999	59.19
2000	59.18
2001	59.79
2002	60.44
2003	60.7
2004	60.54
2005	60.28
2006	59.9
2007	59.53
2008	59.82
2009	60.09
2010	59.86
2011	59.25
2012	59.2
2013	59.14
2014	59.11
2015	59.15
2016	59.07
2017	58.97
2018	58.83
2019	58.7
2020	57.79