Year	%
1973	83.62392
1974	85.50203
1975	79.40753
1976	88.98005
1977	75.76361
1978	76.97476
1979	97.35055
1980	77.60086
1981	77.86358
1982	88.74897
1983	78.9659
1984	81.25366
1985	78.36465
1986	82.4999
1987	76.63986
1988	86.09408
1989	88.30731
1990	89.12503
1991	86.5057
1992	78.34827
1993	77.33585
1995	84.1503
1999	81.87298
2000	84.39036
2001	82.71936
2004	80.223
2005	82.22983
2006	81.94001
2007	87.07768
2008	83.41094
2009	88.40344
2010	88.1921
2011	84.38798