6.0

1997

7.4

1993

6.5

1999

6.8

1977

7.2

1987

8.4

1986

7.7

1998

7.4

1992

6.5

1974

0.0

2000

7.9

2006

8.3

2006

7.0

1970

6.0

1999

8.3

2002

7.2

2004

7.9

2006

0.0

2006

10.0

1976

7.1