1975 7.9

1975 7.7

1975 7.5

1975 7.6

1973 7.4

1972 7.8

1972 7.0

1971 7.2

1970 7.9

1970 7.5

1970 7.0

1969 7.4

1968 6.3

1968 8.3

1967 6.5

1966 8.0

1966 7.2

1966 6.6

1964 6.7

1963 7.0