Year	Percent
1990	69.44
1991	69.66
1992	69.6
1993	69.77
1994	69.99
1995	70.23
1996	70.42
1997	70.67
1998	70.76
1999	70.78
2000	70.79
2001	71.19
2002	71.58
2003	71.96
2004	72.32
2005	72.67
2006	73.02
2007	71.88
2008	72.19
2009	72.11
2010	72.01
2011	71.84
2012	68.93
2013	69.3
2014	71.28
2015	67.04
2016	67.69
2017	69.06
2018	71.96
2019	72.1
2020	66.66