1982

6.1

1971

6.6

1979

6.5

1973

5.2

1981

5.7

1985

6.9

1974

6.5

1986

7.2

1984

6.8

1989

6.0

1972

6.1

1972

6.7

1992

6.8

1973

6.7

1974

5.9

1973

3.5

1973

6.4

1975

6.2

1991

4.0

1980

4.0

1983

6.8

1985

7.1