Year	Percent
1990	68
1991	69.41
1992	70.15
1993	70.23
1994	70.06
1995	69.44
1996	68.85
1997	68.85
1998	68.38
1999	67.4
2000	66.84
2001	66.41
2002	65.96
2003	65.64
2004	65.18
2005	63.1
2006	62.81
2007	63.79
2008	65.41
2009	66.24
2010	67.39
2011	67.51
2012	68.72
2013	68.76
2014	70.67
2015	70.62
2016	70.92
2017	70.37
2018	70.98
2019	70.96