1992

6.3

1974

6.2

1973

4.8

1981

6.7

1980

6.3

1977

6.8

1996

6.8

2004

5.9

2003

6.7

1998

7.2

1974

6.6

1939

7.1

2003

5.3

2017

6.2

2006

6.0

2004

4.8

1987

6.9

2006

7.0

2003

7.2

2000

6.5