Year	Percent
1991	48.94
1992	47.44
1993	46.33
1994	47.1
1995	44.68
1996	51.34
1997	54.18
1998	57.63
1999	56.88
2000	58.64
2001	57.76
2002	56.78
2003	55.55
2004	54.45
2005	52.78
2006	52.7
2007	54.83
2008	57.56
2009	52.69
2010	51.34
2011	50.61
2012	52.02
2013	51.7
2014	50.13
2015	50.48
2016	48.58
2017	48.27
2018	49.23
2019	50.18