1988

6.3

1972

6.8

1979

8.0

1994

7.8

2005

8.1

2008

5.7

1992

6.4

1980

6.0

1991

4.4

1993

8.4

1993

6.9

1984

4.7

2004

6.5

1983

7.1

1985

7.0

1991

7.8

1991

4.5

1975

7.2

1983

7.5

1998

7.1

2001

6.8

1981

6.0

1983

3.3

1997

5.9

2007

6.6