1977

6.8

1971

8.1

1980

5.0

1976

5.6

1972

7.8

1980

6.2

1985

6.5

1978

6.3

1982

5.0

1992

2.8

1987

5.7

1986

6.3

1984

7.3

1981

2.2

1986

4.8

1995

6.2

1968

4.4

1969

2.8

1984

5.6

1979

3.7