1978

4.8

1968

5.8

1967

1.0

1980

6.2

1967

6.5

1977

5.3

1985

4.4

1968

6.8

1997

6.8

2009

7.2

1981

4.2

1995

3.5

2007

5.0

2006

5.5

1973

3.3

1978

4.4

1966

6.0

1988

4.3

1991

4.7

1987

4.4

1983

4.6

1994

2.5