Year	%
1971	93.88729
1972	92.06361
1973	89.25659
1975	93.78682
1976	93.31361
1977	93.29502
1978	91.10651
1979	91.1452
1980	92.34578
1983	93.0305
1984	93.4731
1985	95.20477
1999	99.64039
2000	98.35717
2001	99.77671
2003	99.32016
2007	99.97967
2008	96.29871
2011	94.25422
2015	98.01615