1990

7.4

1992

6.8

2006

6.2

1984

7.5

2008

6.4

2008

7.3

1974

6.8

1934

5.8

1941

5.2

1965

6.6

1997

5.3

2006

6.5

2002

4.5

1956

7.7

1997

7.2

1938

7.0

1937

5.0

1985

6.3

2004

7.1

2009

6.0