Year	Percent
1991	51.95
1992	52.91
1993	53.1
1994	52.54
1995	53.59
1996	52.35
1997	52.8
1998	52.85
1999	50.6
2000	50.44
2001	49.84
2002	49.63
2003	50.4
2004	50.88
2005	51.91
2006	52.77
2007	53.71
2008	54.54
2009	53.19
2010	55.33
2011	57.12
2012	57.49
2013	57.88
2014	57.84
2015	58.04
2016	57.84
2017	58
2018	57.97
2019	57.81
2020	50.78