Year	Percent
1990	71.84
1991	72.07
1992	72.13
1993	72.18
1994	72.39
1995	72.24
1996	71.92
1997	71.4
1998	71.51
1999	71.68
2000	71.19
2001	70.78
2002	70.59
2003	70.27
2004	70
2005	70.47
2006	70.36
2007	69.92
2008	69.7
2009	70.05
2010	70.12
2011	70.45
2012	71.48
2013	72.8
2014	73.53
2015	74.13
2016	75.19
2017	76.11
2018	76.79
2019	76.86