Year	Percent
1990	49.59
1991	49.95
1992	50.35
1993	50.72
1994	51.1
1995	51.35
1996	51.62
1997	51.68
1998	51.63
1999	51.62
2000	51.66
2001	51.65
2002	51.66
2003	51.72
2004	51.8
2005	52.49
2006	53.03
2007	53.96
2008	54.39
2009	55.45
2010	54.99
2011	54.88
2012	54.72
2013	54.54
2014	54.35
2015	54.19
2016	54.01
2017	53.86
2018	53.72
2019	53.52
2020	50.3