Year	Percent
1990	91.31
1991	91.53
1992	91.74
1993	90.92
1994	89.97
1995	88.89
1996	87.67
1997	86.31
1998	84.8
1999	83.17
2000	81.41
2001	82.54
2002	81.52
2003	79.65
2004	80.78
2005	79.94
2006	81.94
2007	84.05
2008	85.05
2009	83.81
2010	82.9
2011	81.95
2012	82.35
2013	83.05
2014	83.27
2015	83.17
2016	82.01
2017	84.3
2018	84.32
2019	85.81