Year	Percent
1990	76.19
1991	76.4
1992	76.91
1993	77.41
1994	77.88
1995	78.35
1996	78.8
1997	79.24
1998	79.67
1999	80.1
2000	80.52
2001	80.94
2002	81.52
2003	82.09
2004	82.65
2005	83.18
2006	83.68
2007	84.16
2008	84.62
2009	85.06
2010	85.5
2011	85.93
2012	86.35
2013	86.76
2014	87.15
2015	87.54
2016	87.91
2017	88.27
2018	88.75
2019	88.57