Year	Percent
1991	63.98
1992	62.75
1993	64.95
1994	64.68
1995	67.02
1996	66.55
1997	67.78
1998	69.3
1999	69.39
2000	69.54
2001	69.89
2002	68.37
2003	67.04
2004	67.47
2005	67.41
2006	69.55
2007	69.39
2008	69.18
2009	64.57
2010	64.5
2011	64.34
2012	64.77
2013	63.22
2014	65.11
2015	66.55
2016	66.05
2017	68.24
2018	68.07
2019	67.97
2020	61.4