1973

5.4

2000

6.2

1997

8.1

1966

7.6

1983

8.1

1966

7.5

1988

7.7

1977

7.3

2006

7.5

1975

7.1

1973

6.6

2004

7.4

2003

6.7

1974

5.2

1986

3.0

1996

7.5

1987

7.7

1996

7.4

1999

6.8

1990

7.8