1979

6.1

1997

5.5

1985

6.0

2004

3.9

2004

6.8

2003

6.2

1998

5.9

1977

6.5

1992

5.5

1986

5.8

1996

5.1

1996

3.8

2001

6.6

1981

5.5

2008

4.3

1995

0.0

1999

3.8

1987

5.8

1979

4.0

1974

5.4