Year	Percent
1990	65.36
1991	65.48
1992	65.98
1993	66.48
1994	66.96
1995	67.42
1996	65.97
1997	66.7
1998	66.92
1999	67.55
2000	67.81
2001	68.09
2002	68.94
2003	69.06
2004	69.96
2005	70.71
2006	70.3
2007	70.17
2008	70.23
2009	70.63
2010	69.65
2011	68.65
2012	69.51
2013	69.56
2014	69.47
2015	69.8
2016	69.74
2017	70.17
2018	70.31
2019	70.93