Year	Percent
1972	67.38735
1973	73.64122
1974	85.78364
1975	95.62352
1976	97.74375
1977	97.8212
1978	99.53583
1979	98.51871
1980	98.87872
1981	95.77277
1982	94.35257
1983	90.48454
1984	93.49149
1985	93.94515
1987	85.21037
1988	87.39135
1989	88.98848
1990	91.92402
1991	93.92533
1992	94.02204
1993	92.82004
1994	95.55689
1996	91.7819
1999	92.05294
2000	94.49699
2002	91.21704
2003	94.19819
2004	94.88967