1959

8.0

1997

6.1

1987

6.9

2005

5.6

1994

6.6

1988

6.7

1966

4.5

2006

7.2

1965

6.8

1946

5.0

2008

4.9

1956

7.5

2006

8.0

1977

7.0

1996

7.0

1938

7.4

1969

6.6

1946

7.8

1998

6.5

2002

6.6