Year	Percent
1990	49.95
1991	50.1
1992	50.11
1993	50.02
1994	49.97
1995	50.09
1996	50.17
1997	50.22
1998	50.28
1999	50.32
2000	50.28
2001	50.34
2002	50.27
2003	50.13
2004	49.96
2005	49.82
2006	49.75
2007	49.68
2008	49.6
2009	49.45
2010	49.21
2011	49.14
2012	49.01
2013	48.83
2014	48.6
2015	48.32
2016	48.13
2017	47.92
2018	47.69
2019	47.44