Year	Percent
1990	70.78
1991	71
1992	71.42
1993	72.24
1994	74.14
1995	73.36
1996	72.75
1997	73.29
1998	74.44
1999	74.68
2000	74.59
2001	74.5
2002	74.38
2003	75.34
2004	73.85
2005	74.43
2006	74.99
2007	75.83
2008	75.95
2009	76.05
2010	74.99
2011	74.94
2012	75.43
2013	76.2
2014	75.07
2015	74.35
2016	74.9
2017	74.24
2018	73.85
2019	74.03