Year	Percent
1990	53.28
1991	53.16
1992	52.83
1993	52.84
1994	52.76
1995	52.76
1996	51.83
1997	50.93
1998	50.1
1999	50.23
2000	50.26
2001	49.97
2002	49.6
2003	49.04
2004	47.82
2005	46.64
2006	45.61
2007	44.72
2008	44.64
2009	42.98
2010	43.13
2011	43.23
2012	43.35
2013	43.52
2014	43.72
2015	43.93
2016	44.03
2017	44.18
2018	44.3
2019	44.39
2020	42.64