Year	Percent
1990	46.98
1991	47.57
1992	48.01
1993	48.09
1994	48.43
1995	48.13
1996	48.12
1997	48.45
1998	48.59
1999	48.64
2000	48.34
2001	48.1
2002	47.99
2003	47.83
2004	47.59
2005	47.31
2006	47.17
2007	46.75
2008	46.62
2009	46.85
2010	46.78
2011	46.64
2012	47
2013	47.14
2014	47.23
2015	47.05
2016	46.61
2017	46.57
2018	46.68
2019	46.42