Year	%
1971	99.52929
1972	95.56155
1973	93.78151
1974	97.22851
1975	97.59911
1976	98.02051
1977	96.07473
1978	97.35543
1979	97.52322
1980	97.93563
1981	98.79506
1983	97.3391
1984	96.2953
1985	96.34601
1986	94.10134
1987	99.17198
1988	92.89809
1989	94.69812
1990	98.83108
1991	93.51331
1992	98.58288
1993	99.0631
1994	99.86644
1995	99.5874
2004	98.35276
2005	98.58697
2006	98.84928
2007	99.89457
2008	99.61347
2010	99.97413
2012	99.70019
2013	99.76481
2014	99.50335
2015	99.56406
2016	98.91265