1973

6.3

1977

6.8

1977

6.0

1977

6.5

1971

6.6

1972

6.7

1979

6.7

1968

6.2

1969

7.1

1974

6.5

1982

6.2

1975

5.5

1978

5.7

1969

6.6

1972

6.1

1971

5.8

1972

6.7

1970

6.3

1980

5.5

1972

6.2

1973

6.7

1971

6.9

1981

6.7

1969

5.9

1969

6.6

1979

6.4

1974

5.9

1973

3.5

1976

5.3

1973

6.4

1977

6.5

1975

6.0

1967

5.8

1973

3.0

1976

6.4

1970

6.3

1974

5.0