Year	Percent
1991	55.18
1992	55.19
1993	55.85
1994	56.17
1995	56.41
1996	54
1997	56.33
1998	57.98
1999	57.24
2000	56.48
2001	58.09
2002	57.48
2003	57.38
2004	56.43
2005	58.35
2006	58.55
2007	60.12
2008	59.62
2009	57.24
2010	56.48
2011	54.08
2012	57.62
2013	57.83
2014	57.34
2015	56.38
2016	54.26
2017	55.3
2018	56.19
2019	57.06
2020	50.27