Year	Percent
1990	74.07
1991	74.32
1992	74.63
1993	74.95
1994	75.28
1995	75.59
1996	75.94
1997	76.29
1998	76.82
1999	75.75
2000	74.43
2001	74.5
2002	74.52
2003	74.49
2004	74.43
2005	74.32
2006	74.16
2007	76.12
2008	77.93
2009	79.61
2010	74.91
2011	79.95
2012	83.86
2013	86.92
2014	86.8
2015	86.86
2016	86.91
2017	87.03
2018	87.13
2019	87.27