Year	Percent
1990	67.62
1991	67.26
1992	67.57
1993	66.78
1994	68.25
1995	68.27
1996	68.29
1997	67.76
1998	68.42
1999	68.68
2000	69.04
2001	68.26
2002	67.16
2003	66.61
2004	66.85
2005	65.87
2006	66.06
2007	68.25
2008	68.63
2009	68.62
2010	69.19
2011	69.43
2012	69.95
2013	69.27
2014	69
2015	68.66
2016	68.37
2017	68.98
2018	69.65
2019	70.2