Year	Percent
1990	67.32
1991	68.12
1992	68.97
1993	69.87
1994	70.84
1995	70.03
1996	68.36
1997	66.81
1998	66.15
1999	65.57
2000	63.47
2001	65.95
2002	63.92
2003	65.36
2004	64.25
2005	64.12
2006	64.31
2007	64.53
2008	64.77
2009	65
2010	66.32
2011	67.31
2012	68.27
2013	67.74
2014	68.53
2015	69.26
2016	68.44
2017	66.74
2018	64.31
2019	63.61
2020	63.87