1962

7.0

1963

7.1

1967

6.6

1969

6.6

1974

6.4

1981

6.5

1985

6.2

1987

6.5

1997

6.4

2004

7.5

2005

7.2

2005

7.4

1981

7.4

1999

7.2

2006

6.3

1966

7.3

1929

6.5

1954

8.0

2002

7.2

1973

6.5