Year	Percent
1990	72.01
1991	72.18
1992	72.2
1993	72.4
1994	72.62
1995	72.58
1996	72.53
1997	72.46
1998	72.37
1999	72.29
2000	72.21
2001	72.14
2002	72.05
2003	70.92
2004	74.41
2005	73.14
2006	71.39
2007	72.55
2008	72.49
2009	73.79
2010	71.94
2011	72.31
2012	75.22
2013	74.4
2014	72.72
2015	73.02
2016	73.85
2017	73.78
2018	75.49
2019	76.18