Year	Percent
1971	39.68801
1974	41.64777
1987	63.20822
1988	64.59666
1995	71.90308
1999	68.95169
2000	71.7798
2001	72.4553
2002	75.84427
2003	80.32841
2008	94.98444
2009	95.94668
2011	92.89476
2013	96.2406
2014	97.57359
2015	97.72773
2016	96.3098