1988

6.3

1972

6.8

1979

8.0

1994

7.8

2005

8.0

2008

5.7

1992

6.5

1980

6.1

1991

4.4

1993

7.0

1984

4.7

2004

6.5

1983

7.1

1985

7.1

1991

7.8

1991

4.6

1975

7.3

1983

7.5

1998

7.1

2001

6.8

1981

6.0

1983

3.3

1997

5.9

2007

6.6