1989

7.2

1995

7.0

1931

8.1

2005

6.9

1995

5.4

1997

5.7

2004

7.2

1985

7.5

2006

5.9

2005

5.8

1992

5.5

2003

6.8

1998

6.0

1984

5.5

2000

6.8

2008

6.9

2012

4.0

1955

7.3

1972

6.2

1922

7.7