Year	Percent
1986	89.8
1991	92.4
1996	95.5
1999	96.6
2000	97.6
2002	97.8
2006	95.5
2007	97.8
2010	96.9
2011	98.7
2012	98.8
2013	98.6
2014	97.7
2015	99.6