2004

6.4

1992

6.7

2007

7.1

2008

6.2

2007

5.5

2008

5.0

2006

5.7

1998

6.4

1986

6.7

2004

5.8

2003

4.0

1976

7.6

1962

7.4

2003

6.1

2000

7.0

1991

6.1

2007

6.2

1931

8.1

1993

5.5

1995

6.5