1992

5.8

1996

6.4

1994

4.5

1988

8.0

2002

6.3

1988

5.0

2001

6.8

1962

7.7

2003

7.2

1997

6.7

2002

6.6

1999

7.4

1955

7.5

1955

6.8

1960

6.7

1978

6.5

1999

7.1

2001

7.8

1993

6.7

1938

6.9