Year	Percent
1990	69.54
1991	69.66
1992	70.89
1993	70.15
1994	71.51
1995	72.47
1996	72.67
1997	72.9
1998	73.11
1999	72.71
2000	73.25
2001	75.2
2002	73.94
2003	73.43
2004	73.23
2005	73.76
2006	74.59
2007	75.69
2008	76.15
2009	76.4
2010	76.28
2011	76.69
2012	76.35
2013	75.93
2014	76.39
2015	76.01
2016	75.84
2017	75.51
2018	75.18
2019	75.28