1964

6.9

1980

5.5

1974

6.2

1974

7.3

1967

6.7

1982

6.2

1994

6.9

1971

7.0

1992

5.5

1970

7.4

1977

7.2

1973

5.1

1969

5.7

1988

5.9

1972

6.9