Year	Percent
1990	68.96
1991	69.08
1992	69.06
1993	69.24
1994	69.44
1995	69.49
1996	69.53
1997	69.57
1998	69.6
1999	69.63
2000	69.66
2001	69.68
2002	69.68
2003	68.57
2004	71.95
2005	70.88
2006	68.59
2007	69.76
2008	69.8
2009	71.11
2010	69.02
2011	69.29
2012	72.4
2013	71.34
2014	69.6
2015	69.64
2016	70.38
2017	70.57
2018	72.02
2019	72.66
2020	70.25