Year	Percent
1990	76.6
1991	77.99
1992	78.28
1993	79.07
1994	79.74
1995	80.26
1996	80.67
1997	80.93
1998	81.14
1999	82.38
2000	82.65
2001	80.88
2002	81.61
2003	81.75
2004	82.74
2005	84.58
2006	84.52
2007	85.36
2008	85.73
2009	85.61
2010	86.37
2011	84.78
2012	85.02
2013	85.36
2014	85.67
2015	85.1
2016	85.18
2017	84.89
2018	85.02
2019	84.87