Year	Percent
1976	79.71842
1977	81.52394
1979	87.67297
1980	85.0067
1981	86.23545
1984	88.89234
1985	85.53788
1986	86.53422
1987	89.99856
1988	92.12242
1989	94.76948
1990	95.29827
1991	92.40954
1993	88.8793
2000	86.36429
2001	80.84027
2002	86.67759
2004	86.59954