1995

6.2

1998

5.6

1980

3.0

1997

6.7

1973

6.4

2006

6.2

1979

6.8

1981

6.1

1978

5.0

1982

7.5

1971

5.4

1976

7.2

1979

5.1

1973

5.0

1988

6.4

1988

6.7

1981

6.7

1982

6.3

1982

7.4

1986

4.7