Year	Percent
1987	61.3
1994	98.7
1999	99.1
2004	98.2
2005	80
2006	82.6
2007	84.1
2008	85.8
2009	87.7
2010	89.2
2011	91.1
2012	93.1
2013	94.7
2014	96.3
2015	95
2016	96.7