Year	Percent
1990	74.87
1991	74.9
1992	74.92
1993	74.92
1994	74.92
1995	74.9
1996	74.91
1997	74.92
1998	74.9
1999	74.84
2000	74.74
2001	74.17
2002	73.6
2003	73.02
2004	72.46
2005	71.93
2006	71.4
2007	71.09
2008	70.79
2009	70.47
2010	70.13
2011	69.75
2012	69.35
2013	68.92
2014	68.48
2015	68.02
2016	68.02
2017	67.95
2018	67.89
2019	67.81
2020	66.21