1981

6.5

1997

6.4

2003

8.0

2007

5.6

1924

8.1

2008

8.5

1989

7.2

2005

7.7

2004

4.6

1992

6.9

2004

7.9

1996

4.2

1984

6.0

1990

6.2

2007

7.4

1982

6.6

1991

0.0

1963

7.9

2012

6.7

2006

6.6