1960

8.4

2005

7.8

1988

7.8

2005

6.4

1972

7.1

1972

8.0

1993

5.6

1989

6.0

1936

4.9

2003

6.3

1997

6.8

1993

5.0

2003

4.8

1997

6.9

2002

5.4

2007

6.4

2007

6.7

1996

5.6

1947

6.0

1969

6.0