1974

5.5

2003

5.9

1985

6.2

2004

7.9

1995

6.6

1972

7.3

2000

7.2

1969

5.8

2007

7.8

2007

5.9

2009

7.6

1994

6.4

1982

6.9

1960

5.8

2004

6.2

1925

8.0

1957

7.8

1974

7.9

2006

7.0

1993

5.7