Year	Percent
1990	49.9
1991	50.17
1992	50.46
1993	50.75
1994	51.06
1995	51.39
1996	51.69
1997	51.54
1998	51.39
1999	51.25
2000	51.12
2001	51.01
2002	50.91
2003	50.8
2004	50.68
2005	50.53
2006	50.37
2007	50.16
2008	49.92
2009	49.67
2010	49.41
2011	49.19
2012	48.99
2013	48.87
2014	48.78
2015	48.67
2016	48.58
2017	48.5
2018	48.5
2019	48.53
2020	46.92