Year	Percent
1991	48.64
1992	48.33
1993	47.93
1994	47.59
1995	47.3
1996	47.16
1997	47.07
1998	47.05
1999	47.09
2000	47.24
2001	46.63
2002	45.71
2003	46.55
2004	46.89
2005	46.92
2006	47.26
2007	48.2
2008	49.01
2009	49.52
2010	50.11
2011	50.57
2012	50.96
2013	50.97
2014	50.95
2015	50.86
2016	50.76
2017	50.62
2018	50.45
2019	50.23
2020	47.69