Year	Percent
1983	93.17181
1984	92.89881
1986	93.75754
1987	94.17392
1988	95.06173
1989	94.71464
1990	94.74306
1991	94.7891
1992	94.47588
1993	94.59244
1994	94.54598
1995	94.6416
1996	94.87499
1997	94.88924
1998	94.66646
1999	94.63016
2000	95.26101
2001	96.07185
2002	95.50731
2003	95.03825
2004	95.36595
2005	95.24742
2006	94.76433
2007	95.22094
2008	95.46304
2009	94.99555
2010	94.71708
2011	94.83232
2012	94.79553
2013	94.67527
2014	94.71266
2015	94.86423
2016	94.3892
2017	94.92732