1975

6.7

1982

6.1

1974

6.5

2008

5.7

1972

6.1

1983

7.2

1987

7.1

1981

6.4

1973

6.7

1999

6.3

1975

7.0

1956

7.1

2008

6.8

2014

5.7

2017

10.0

1958

7.5

2002

5.3

1993

6.4

1972

7.7

1983

5.8