Year	%
1971	72.10667
1974	81.44108
1975	88.43635
1976	86.66032
1977	88.17251
1978	93.38583
1993	58.73281
1998	65.83837
1999	66.67118
2000	68.25152
2001	70.70526
2002	71.1615
2003	71.48929
2004	76.16042
2005	75.59367
2006	77.08833
2008	94.29466
2009	93.91816
2010	93.06836
2011	96.01322
2012	98.25261
2013	99.90298
2014	95.87593
2015	98.86893
2016	99.20505
2017	100