Year	Percent
1990	48.75
1991	49.03
1992	49.28
1993	49.47
1994	49.67
1995	49.8
1996	49.89
1997	50
1998	50.1
1999	50.22
2000	50.4
2001	50.48
2002	50.56
2003	50.68
2004	50.83
2005	50.95
2006	51.09
2007	51.24
2008	51.38
2009	51.5
2010	51.63
2011	51.75
2012	51.84
2013	51.91
2014	51.95
2015	51.93
2016	51.83
2017	51.8
2018	51.76
2019	51.66
2020	48.31