Year	Percent
1990	49.52
1991	50.28
1992	50.5
1993	50.21
1994	49.75
1995	48.99
1996	48.41
1997	48.31
1998	47.92
1999	47.16
2000	46.69
2001	46.27
2002	45.82
2003	45.47
2004	45.03
2005	44.3
2006	43.89
2007	44.55
2008	45.33
2009	45.29
2010	45.94
2011	45.69
2012	46.15
2013	45.96
2014	47
2015	46.93
2016	46.76
2017	46.54
2018	46.58
2019	47.45
2020	46.27