Year	Percent
1990	62.86
1991	62.86
1992	62.91
1993	62.96
1994	63.06
1995	63.04
1996	62.98
1997	62.91
1998	62.78
1999	62.65
2000	62.61
2001	62.55
2002	62.61
2003	62.52
2004	62.44
2005	62.36
2006	62.35
2007	62
2008	61.63
2009	61.25
2010	60.86
2011	60.49
2012	60.11
2013	59.72
2014	59.32
2015	58.91
2016	58.93
2017	58.95
2018	59.01
2019	59.12