1970 1	2.545
1971 2	2.469
1972 3	2.392
1973 4	2.193
1974 5	1.901
1975 6	1.718
1976 7	1.645
1977 8	1.546
1978 9	1.433
1979 10	1.289
1980 11	1.136
1981 12	1.041
1982 13	1.000
1983 14	0.984
1984 15	0.964
1985 16	0.955
1986 17	0.969
1987 18	0.949
1988 19	0.926
1989 20	0.880
1990 21	0.839
1991 22	0.822
1992 23	0.812
1993 24	0.802
1994 25	0.797
1995 26	0.782
1996 27	0.762
1997 28	0.759