Year	Percent
1971	50.852
1974	53.15669
1987	75.26575
1988	76.52124
1995	81.25179
1999	76.7674
2000	79.37666
2001	78.8544
2002	82.11545
2003	83.06505
2008	94.82291
2009	95.30712
2011	92.52932
2013	93.73603
2014	95.2738
2015	95.41865
2016	94.25066