Year	Percent
1990	73.17
1991	73.04
1992	73.13
1993	73.18
1994	73.13
1995	72.94
1996	72.32
1997	72.38
1998	72.12
1999	70.45
2000	70.48
2001	69.47
2002	68.21
2003	70.69
2004	70.71
2005	70.59
2006	72.84
2007	73.23
2008	74.33
2009	74.18
2010	73.99
2011	74.84
2012	74.97
2013	75.27
2014	75.4
2015	76.8
2016	77.63
2017	78.89
2018	79.12
2019	78.9