1980 6.9

1979 6.4

1979 7.8

1979 7.3

1979 7.8

1978 6.4

1978 7.2

1978 8.0

1977 8.2

1977 7.0

1977 5.3

1977 7.9

1977 4.0

1976 5.3

1976 6.6

1976 8.0

1976 4.4

1975 4.6

1975 4.9

1975 7.7