1967

6.5

1985

6.7

1980

7.3

1997

6.6

1973

7.0

1993

6.7

1999

7.6

1972

6.8

2000

6.7

1999

5.5

1942

7.8

2006

4.9

2016

6.7

1963

7.0

1984

6.8

1982

5.2

2005

6.3

2008

6.2

1965

6.8

2003

5.5