1974

6.3

1997

1.0

1992

7.4

1984

3.8

1980

6.3

1998

2.6

1976

2.0

1999

6.7

1987

4.3

1989

5.1

1994

3.0

1980

6.4

1982

5.4

1993

7.1

2001

5.5

1983

4.7