Year	Percent
1990	59.11
1991	59
1992	59.08
1993	58.58
1994	58.69
1995	58.51
1996	58.22
1997	58.09
1998	57.83
1999	57.69
2000	57.5
2001	57.08
2002	57.11
2003	57.12
2004	57.55
2005	57.69
2006	57.95
2007	58.29
2008	58.27
2009	57.86
2010	58.04
2011	58.25
2012	58.54
2013	58.59
2014	58.63
2015	58.75
2016	58.9
2017	58.99
2018	59.19
2019	59.41
2020	59.1