Year	Percent
1990	49.99
1991	49.88
1992	50.11
1993	50.27
1994	49.99
1995	50.33
1996	50.01
1997	50.22
1998	50.1
1999	50.21
2000	50.3
2001	50.26
2002	49.98
2003	50.51
2004	50.72
2005	50.52
2006	50.21
2007	50.05
2008	49.79
2009	49.8
2010	49.82
2011	49.82
2012	49.18
2013	48.82
2014	48.01
2015	47.17
2016	46.35
2017	45.49
2018	45.43
2019	45.37
2020	42.63