1975

6.7

1992

6.3

1974

6.2

1973

4.8

1975

6.8

1977

6.8

1981

6.7

1977

6.8

1972

6.7

1976

6.2

1996

6.8

2004

5.9

1972

6.7

2003

6.7

2001

5.9

2003

5.7

1988

7.3

1998

7.2

1989

5.8

1983

7.2