Year	Percent
1991	45.03
1992	44.96
1993	44.96
1994	44.99
1995	43.49
1996	42
1997	40.56
1998	41.65
1999	42.68
2000	43.75
2001	43.75
2002	43.64
2003	43.55
2004	43.5
2005	43.71
2006	44.08
2007	44.43
2008	44.7
2009	44.64
2010	44.81
2011	46.71
2012	48.51
2013	49.55
2014	49.74
2015	47.98
2016	46.19
2017	46.78
2018	47.28
2019	47.65
2020	46.79