Year	Percent
1990	46.65
1991	46.87
1992	46.94
1993	47.18
1994	47.37
1995	47.36
1996	47.36
1997	47.02
1998	46.71
1999	46.42
2000	46.16
2001	45.93
2002	45.73
2003	45.56
2004	45.41
2005	45.29
2006	45.2
2007	45.13
2008	45.08
2009	45.06
2010	45.32
2011	45.58
2012	45.88
2013	46.96
2014	44.78
2015	45.32
2016	45.86
2017	46.39
2018	46.41
2019	46.37