1980

8.4

1985

4.8

1983

6.3

1985

7.4

1999

4.2

1981

6.6

1975

5.8

1981

8.1

1995

1.0

2006

7.1

1987

6.8

1984

5.0

1968

6.0

1969

7.5

1965

4.0

1986

7.0