1976

6.5

1999

7.1

2001

6.2

1960

7.3

1966

8.0

1960

7.5

1976

4.5

2001

7.0

2007

6.2

2003

8.3

2006

7.9

1956

6.5

2000

6.8

2004

6.1

2005

6.8

1998

7.3

1999

6.8

1991

7.6

1990

6.7

1985

6.7