Year	Percent
1990	59
1991	58.72
1992	58.47
1993	58.19
1994	57.93
1995	57.73
1996	57.61
1997	58.34
1998	59.3
1999	58.1
2000	57.38
2001	57.53
2002	57.99
2003	56.47
2004	58.98
2005	59.21
2006	59.29
2007	59.77
2008	59.49
2009	59.43
2010	59.24
2011	58.07
2012	57.74
2013	57.46
2014	57.73
2015	57.41
2016	56.73
2017	58.52
2018	58.87
2019	57.99
2020	57.38