Year	Percent
1990	67.3
1991	67.34
1992	67.39
1993	67.94
1994	68.77
1995	69.56
1996	68.88
1997	71.17
1998	72.32
1999	72.54
2000	71.37
2001	74.45
2002	74.55
2003	74.84
2004	74.29
2005	76.79
2006	76.21
2007	76.87
2008	77.8
2009	78.15
2010	77.29
2011	76.97
2012	79.85
2013	79.79
2014	79.3
2015	78.39
2016	76.77
2017	77.16
2018	79.32
2019	82.1