1959

6.2

1956

6.5

1993

6.5

1961

8.1

1995

4.6

1999

5.9

1958

7.0

2001

6.0

1962

6.9

1957

7.7

1996

7.1

1988

6.5

2004

7.9

1971

6.0

1968

7.1

1998

6.2

2012

6.3

1955

6.2

1980

6.8

1985

6.8