Year	Percent
1990	51.31
1991	49.94
1992	50.64
1993	50.49
1994	51.16
1995	51.63
1996	52.3
1997	52.08
1998	53
1999	53.39
2000	53.37
2001	52.37
2002	52.71
2003	53.09
2004	53.92
2005	53.73
2006	53.76
2007	53.44
2008	53.22
2009	53.46
2010	53.4
2011	52.84
2012	52.64
2013	52.4
2014	52.07
2015	52.19
2016	52.25
2017	52.16
2018	52.09
2019	52.24
2020	51.35