Year	Percent
1990	73.95
1991	74.01
1992	74.06
1993	74.08
1994	74.08
1995	74.07
1996	74.05
1997	74.03
1998	74.09
1999	74.09
2000	74.07
2001	74.05
2002	73.84
2003	73.63
2004	73.45
2005	73.8
2006	74.01
2007	74.08
2008	74.26
2009	74.67
2010	74.77
2011	75.25
2012	74.88
2013	74.81
2014	75.59
2015	75.3
2016	75.52
2017	73.51
2018	73.73
2019	74.65