1951

6.9

2008

5.5

2020

5.8

1976

4.9

1985

6.1

1939

7.5

2004

7.2

1995

8.0

1967

7.4

1972

6.2

1993

7.4

1998

6.5

1997

6.1

2001

6.8

1944

7.6

2000

6.3

2008

4.9

1968

6.9

2002

6.2

2008

6.5