1977

8.2

1956

7.7

1939

7.6

1998

6.1

2002

6.1

2004

6.9

2003

7.2

1929

4.0

1997

6.6

2000

6.0

1962

7.8

2001

5.3

1986

5.3

1970

7.1

1981

7.9

1984

7.3

1943

7.2

2003

5.9

1992

5.9

2005

3.5