Year	Percent
1991	56.96
1992	56.83
1993	56.91
1994	57.83
1995	56.28
1996	54.51
1997	52.99
1998	50.78
1999	49.56
2000	50.31
2001	49.78
2002	50.1
2003	50.49
2004	50.51
2005	51.16
2006	51.24
2007	51.42
2008	51.4
2009	50.1
2010	50.57
2011	50.95
2012	50.86
2013	51.67
2014	49.4
2015	49.76
2016	49.46
2017	49.33
2018	49.57
2019	49.72
2020	47.52