Year	Percent
1991	52.15
1992	50.75
1993	49.21
1994	47.6
1995	47.39
1996	47.22
1997	47.34
1998	47.53
1999	48.39
2000	49.13
2001	47.83
2002	46.57
2003	45.23
2004	46.67
2005	48.06
2006	49.44
2007	50.73
2008	51.92
2009	52.78
2010	49.35
2011	52.78
2012	55.68
2013	58.15
2014	58.23
2015	58.34
2016	58.36
2017	58.42
2018	58.42
2019	58.41
2020	57.1